Pierre Borderies

Alia Hamadi

L Villard

C Albinet

T Koleck

Cesbio

Electromagnetic Simulations of Radar Backscatter from Tropical Forests: Effects of bio/geo-physical parameters

Keywords: electromagnetic modelling, P-Band SAR, Tropical forests, Temporal coherence, biophysical parameters. I

This paper deals with the modelling of time series of polarimetric backscattering and temporal coherence of a tropical forest at P Band. The experimental data show that in the dry season daily cycles of both observables are present and that they are linked to the wind and to the dielectric changes of the canopy. To retrieve these observations, a descriptive model for the forest and an electromagnetic model for the scattering are used. First, canonical studies are carried out about single branches scattering behavior with the goal of highlighting further results. Then, dielectric constant variation and displacements due to the wind are applied to the model and it is shown that they reproduce efficiently the experimental time series.

INTRODUCTION

P-band microwaves (wavelength around 70 cm) can be used for their capability to penetrate through dense media, such as tropical forests. Being sensitive to the whole vegetation volume, measures derived from P-band SAR (Synthetic Aperture Radar) acquisitions such as the backscattered intensity or the effective canopy height can be correlated to the forest above ground biomass (AGB). Such features have originated the Biomass space borne mission [START_REF] Le T Oan | The BIOMASS Mission : Mapping global forest biomass to better understand the terrestrial carbon cycle[END_REF] which aims at mapping globally biomass stocks and changes using a SAR operating at 430 MHz.

Nonetheless, various geophysical parameters independent from the biomass are liable to impact SAR measurements and thereby to bring perturbations on retrieval algorithms. For instance, the temporal variations linked to vegetation water content (VWC) and wind conditions have been emphasized by the TropiScat Radar experiment [START_REF] Albinet | T ropiscat: A ground based polarimetric scatterometer experiment in tropical forests[END_REF] (scatterometer on the top of the Guyaflux tower) recently conducted over the Paracou test site (French Guiana). Indeed, the time series of the backscattering coefficient and the temporal Radar coherence acquired during this campaign have exhibited some significant and regular daily changes. It is important to interpret such variations in the context of the Biomass mission. It presents also a broader interest in the retrieval of bio, geophysical properties of tropical forests for other applications and objectives.

For a better understanding of these phenomenons, a sensitivity analysis has been performed from electromagnetic simulations, performed with MIPERS (Multi-static Interferometric and Polarimetric Electromagnetic model for Remote Sensing) [START_REF] Villard | Backscattering border effects for forests at C-Band[END_REF] [START_REF] Villard | Topography effects on forest radar scattering, consequences on biomass retrieval[END_REF]. The input data of the model are based on a discrete description of the natural scatterers, incorporating in-situ data and allometric relations. This model affords the polarimetric backscattering coefficient. In addition, it is coherent and so temporal coherences as well as Pol-InSAR coherences can be simulated and enable to quantify the impact of dielectric changes (linked to VWC) or to displacements of the scatterers (due to wind conditions).

In this paper, EM simulations are achieved with the MIPERS model and confronted to the experimental results of the ground based scatterometer TropiScat. Section II recalls the main features of the modelling, first for the individual scatters and later for the global approach. Section III deals with the VWC variations and the wind influence.

II. ELECTROMAGNETIC MODELLING

A. Individual Scattering Elements

At P band the leaves present a small interaction with the electromagnetic waves so that only branches and trunks are usually represented. The most commonly used approximation to account for them is the homogeneous finite dielectric cylinders. The model used for this purpose here is described in [START_REF] Kong | Scattering of Electromagnetic waves: Advanced T opics[END_REF]. It can be applied with confidence in P-band since its accuracy has been tested in these conditions of shape and frequency in [5]. Fig. 1 displays the comparison of the scattering diagram obtains with a numerical method (FDTD), the analytical model and an alternative one. As specular backscattering at normal incidence (with respect to the scattering element) usually drives the global backscattering and specular scattering at the incidence angle drives the double bounce (interaction with ground) contribution, one can check that that the agreement is very good for a typical forest scatter.

Apart from its shape, such scattering diagram is induced by the dielectric constant itself tied to the VWC. Fig. 2 presents the variation of the backscattering coefficient at normal incidence of a dielectric cylinder representing a typical branch: a length of 3m and a radius that varies from 0.5 cm for small, high order branches to a few cm for primary branches and grows up to trunks dimens ions(25 cm radius). Note that here HH and VV refer the incident wave polarization versus the cylinder positioned vertically. This plot is reproduced for various moisture contents from 30% which corresponds to dry conditions to 80% for very wet conditions inside the wood, even if the highest values may be somehow exaggerated. These quantities are certainly interrelated since large radius branches are certainly dryer than the extremities which are thin. Actually, distribution of moisture inside a tree is a complex topic since it is variable according to the height of the trunk and in the branches according to the distance to the trunk, and is subject to abrupt diurnal as well as seasonal changes [START_REF] Mcdonald | Diurnal and spatial variation of xylem dielectric constant in norway spruce (picea abies [l.] karst.) as related to microclimate, xylem sap flow, and xylem chemistry[END_REF]. However, it is interesting to look at the influence of thes e parameters independently.

For this range of values, in VV, whatever the moisture content, only one resonance peak and subsequent dip appear. The dip becomes weaker as moisture content increases: indeed, in this case, complex permittivity increases both in real and imaginary part, which induces a smaller penetration into the cylinder and also a stronger attenuation inside it. In the resonance zone, the Radar Cross Section is not univocally related to the volume of the scatterer (and hence to biomass): increasing biomass may indeed correspond to lowering RCS. In the Rayleigh zone, before the first resonance peak, there is a very strong increase of RCS with radius. This monotonous growing behaviour exists for all cylinders which radii are less than 4 cm. Beyond the resonance, there is still a growth of RCS with radius (hence with biomass) : the range of radii involved here makes it more interesting for specular direction. This slow growth can be interpreted as the consequence of increasing the effective section of the cylinder in the high frequency regime. Note the very strong differences in VV and HH behaviour, both in the Rayleigh and resonance regions, which results in a vertical scatterer roughly saturating at 2-3cm whereas a horizontal one saturates at 8-10 cm.

B. The Mipers code

A detailed description can be found in [START_REF] Villard | Backscattering border effects for forests at C-Band[END_REF] with the adequate references. The model is able to encompass infinite size forests as well as finite ones whatever the radar resolution. To compute the electromagnetic response of the medium, Born extended approximation is used. The contributions of all the scatters present in the scene are coherently summed for the various combinations of all polarizations: this approach is fully polarimetric and phase preserving so it allows full polarimetric, interferometric and POLINSAR simulations.

For each scatter we can then consider several mechanisms:

Volume contribution: As developed in the previous section, each element is envisioned as a discrete scatter of known scattering matrix. The influence of the surrounding scatters is accounted for with Foldy-Lax approximation through the use of an effective propagation constant (attenuation) derived from the forward scattering theorem. Some geometrical computations are performed to account for all intersection points if any between emitter-scatter ray and all vertical and horizontal boundaries of the layers. This process is repeated for the scatter-receiver ray. Then complex transmittivity matrices factor between emitter and scatter and between scatter and receiver are computed taking into account all eventual path lengths in each layer. This scattering component is sensitive to VWC.

Soil contribution : The Integral Equation Method is used.

To account for speckle effects and fit with observed data, we spread the backscattering coefficient on the pixel surface with sub-sampling it and attributing to it a random phase, which traduces large scale roughness. This scattering component is sensitive to VWC and to soil moisture, but is scarcely significant.

Volume/soil interaction: For each path considered, similar geometrical computations are implemented and subsequent transmissivity matrices derived. For each mechanism, soil specular reflection is accounted for through modified Fresnel coefficients. This scattering component is sensitive to VWC and to soil moisture.

The location of the scatters in the volume canopy may be driven by a multi-layer description of the forest or by a tree description which is illustrated by Fig. 3. In addition to the above geometrical descriptors, moisture content has to be given for the soil and for each individual scatter, which permits to parametrize the changes in dielectric constants for both soil and vegetation. Note that the construction of the code permits inherently to simulate the effect of displacements induced by wind as was done formerly in [START_REF] Ruiz | Modelling of electromagnetic waves interaction with forest canopies[END_REF] for temperate forests.

The output of the code is the complex scattering coefficient, which gives the backscattering coefficient with averaging and the temporal coherence which accounts for the changes of all nature observed in the observed scene between two dates The value of the coherence between a measurement at a given time S1 and the reference measurement S2 at another time is computed with

    2 2 2 1 * 2 1 ) ( . ) ( ) ( . ) ( r S r S r S r S pq pq pq pq pq  (1)
with

V H p  and V H q 

III. TROPICAL FOREST MODELLING A. Observed diurnal cycles

The description of the experiment can be found in [START_REF] Albinet | T ropiscat: A ground based polarimetric scatterometer experiment in tropical forests[END_REF] and some results in [START_REF] Hamadi | Temporal survey of polarimetric pband scattering of tropical forests[END_REF]. Fig. 5 displays some daily cycles of the Radar observables during the dry season. Those results are obtained in the absence of rain, which yields a more simple interpretation. For the temporal coherence, reference is taken at 12 p.m. One can observe a regular decrease during the night up to 6 a.m., and this regularity is retrieved after 6 p.m. up to midnight. At daytime, strong oscillations appear, associated with wind speed increase. In agreement with [START_REF] Assis | Comments on Some radio Wave Propagation Mechanisms in the Amazon region[END_REF] and our own observations, tropical forests presents a completely different behavior during the night when they look motionless and during the day when their motion is highly apparent. P band temporal coherence accounts for this typical behavior and then the sources of the decorrelation are filtered: during the night, it is due to dielectric changes and during the day it is due to dielectric changes and to scatters displacements because of wind ( or turbulence).

It is to note that the scene observed by the Tropiscat experiment presents an important slope, of around 10%. Consequently, double bounce contribution is strongly reduced. Then, a minor influence of soil moisture content is expected. This was verified experimentally, since Radar observables were found to be poorly correlated to the interval of time between the measurement and the last rain corresponding to a humidification of soil, but rather to an interval of time suggesting an influence of rain on the VWC of some trees components. For these reasons, the changes in the temporal coherence during the night are considered to be originated by the VWC variation in the branches and trunks. The displacement of the scatters do not affect the intensity, and on the time series of the backscattering coefficient the regularity is not affected by the day/night change: in this case, major source of temporal changes is the dielectric constant evolution due to the evapo-transpiration daily cycles.

B. Impact of dielectric constant changes

The forest description of the Guyana forest is done according to in-situ measurements and gives the input data of the MIPERS code. For the VWC, measured values over tropical forests are lacking to our best knowledge and thereby the values reported in [START_REF] Mcdonald | Diurnal and spatial variation of xylem dielectric constant in norway spruce (picea abies [l.] karst.) as related to microclimate, xylem sap flow, and xylem chemistry[END_REF] for temperate forests were chosen. The corresponding complex dielectric constants are displayed on Fig. 4. The results of the simulation agree with the changes observed between 12 p.m and 6 a.m.. The orders of magnitude are coherent, including the fact that there is a stronger decorrelation in HH than in the other polarizations.

C. Impact of Convective Wind

Based on vectorial modeling of the wind speed field [START_REF] Beaudoin | Simulation levels of detail for plant motion[END_REF][12], the displacements of the scatterers are deduced from the transposition of wind velocity vectors into angular velocities, assuming that only the branches orientation angle is affected. Considering several magnitude of wind speed IV. FUTURE PROSPECT S The electromagnetic model has shown its ability to reproduce the time series observed on tropical forests. The benefits which can be withdrawn with its use in system simulators is very broad. Future prospects include the continuation of this analysis and its extens ion to tropical forest over a flat area.

Fig. 1

 1 Fig. 1 Scattering diagram in VV of an homogeneous cylinder of permittivitty (25.,-1.) , radius 5 cm and length 1.5 m. Incident plane wave is at P band and incidence of 30 deg. T he 3 represented curves correspond to the FDT D and both Karam and T sang analytical approximations. T he diagrams are represented in the incidence plane in the upper hemisphere ( which incorporates the backscatteringdirection). T he cylinder is vertical.

Fig. 2 :

 2 Fig. 2: Variation of the backscattering coefficient of a dielectric cylinder representing a typical branch of length 3m and varying radius in m; cylinder axis is vertical and incident illumination is at normal incidence. 4 values of moisture content are considered

Fig. 3 :

 3 Fig. 3 : Example of tropical forest stand model used by MIPERS to simulate SAR measurements: left, layer description; right: trees set description.

Fig. 4 :

 4 Fig. 4: Complex dielectric values associated to each scenario of VWC

Fig. 5 :

 5 Fig. 5 : T emporal variations in the dry season. Left : coherence derived from HH, HV and VV scattering coefficients respect ively in red, blue and green during 24 hours ( reference is at 12 p.m.) The bottom curve is the wind speed. Right : backscattering coefficient over a period of 7 days in the dry season.

Fig. 6 :

 6 Fig. 6: Decorrelation resulting from the simulated total backscatter due to changing values of permittivity given by Fig. 4

Fig. 7 :

 7 Fig. 7: Decorrelation resulting from the simulated total backscatter due to bigger and bigger wind speed considering the conversion of wind speed into branches orientation changes and spatial displacements.

ACKNOWLEDGMENT

The authors wish to thank CNES for supporting this modelling work in the frame of the TOSCA activities. The authors would like to thank Lilian Blanc and Benoit Burban with 'Ecologie des Forets de Guyane', and Damien Bonal with the Institut National de la Recherche Agronomique, for their welcome and help with the Guyaflux tower.


Simon Bulmer

Christian Lequesne

New Perspectives on EU-Member State Relationships 1

This paper aims to review the "state of the art" for examining EU-member state relations. It recognises first of all that EU-member state relationships are interactive. Member states are key actors in making EU policy, and their role in this process is central to policy-making studies. However, European integration has an important impact upon the member states: the phenomenon that has come to be termed Europeanization. We review the literatures concerned with these two directions of flow: the analytical issues raised and the theoretical perspectives deployed. We then turn to the empirical literature on EU-member state relationships, and how it operationalises the theoretical literatures (if at all). This empirical literature tends to be organised in two ways: individual or comparative studies of member states' relationships with the EU; or studies of the impact of the EU on types of political actor/institution or on policy areas/sectors. We review both these literatures. On the basis of the identified strengths and weaknesses in the different literatures examined, we suggest a research agenda for future theoretical and empirical work.

Résumé

Cette étude est une revue critique de la littérature portant sur la relation entre l'Union européenne et ses Etats membres. Elle part du constat que ces relations sont interactives. Les Etats membres restent des acteurs incontournables de l'élaboration des politiques publiques dans l'Union européenne et leur rôle apparaît donc essentiel dans l'analyse du policy-making. Cependant, l'intégration européenne a aussi un important impact sur les Etats membres eux-mêmes : le phénomène est souvent décrit à l'aide du terme "européanisation". L'étude fait une recension détaillée de ces influences mutuelles, des problèmes analytiques qu'elle soulève et des perspectives théoriques qu'elle permet de déployer. Elle examine ensuite la littérature empirique qui s'est intéressée à la relation entre l'Union européenne et les Etats membres, et sur la manière dont cette relation est rendue opérationnelle par la littérature théorique. Cette dernière comprend en effet deux dimensions : des études monographiques et comparatives sur les relations entre les Etats membres et l'Union européenne ; des études sur l'impact de l'Union européenne sur certains acteurs et institutions nationales, ou sur certaines politiques ou secteurs d'activités économiques. Sur la base de cet examen critique, nous suggérons enfin un agenda de recherche permettant de progresser au double plan de l'analyse théorique et empirique.

INTRODUCTION: WHY MEMBER STATES MATTER

It is scarcely a controversial point to argue that "member states matter" in the study of integration and governance in the European Union. They matter as key actors in EU decision-making, whether in the European Council or Inter-governmental Conferences, on the one hand, or in the more routine policy decisions of the Council and its supporting committee structure, on the other. They are also key actors in the implementation of European policy: in providing the administrative sub-structure on which the EU depends in most areas, if its policies are to achieve their goals. Helen Wallace summarises the situation thus:

Most of the policy-makers who devise and operate EU rules and legislation are from the member states themselves. They are people who spend the majority of their time as national policy-makers, for whom the European dimension is an extended policy arena, not a separate activity. Indeed much of EU policy is prepared and carried out by national policy-makers and agents who do not spend much, if any, time in Brussels (H. Wallace, 2000: 7).

Member states also matter in the theoretical and analytical debates concerning integration and governance. An approach such as intergovernmentalism places the national governments at the heart of an understanding of the integration process. However, no theoretical or analytical approach designed to understand integration or the EU's political system can neglect the role of member states. How each takes them into account will be explored later in this paper. In this introduction we confine ourselves to a short review of the empirical reasons why member states matter. The theoretical and analytical aspects are considered in a second part of the paper. A third part of the paper considers the analytical issues which arise from "inside-out" studies of member state-EU relations. The fourth part deals with analytical issues associated with "outside-in" approaches, especially Europeanization. A final section sets out a kind of research agenda, comprising some areas of EU-member state interaction that remain under-researched.

Before we proceed further we need a clear understanding of what we mean by "member states". Here we use that term as a shorthand to comprise all political actors and institutions within a member state. We are not using it as a synonym for national governments. The latter usage, prominent in early intergovernmentalist accounts of the EU, brings with it a number of problems. First of all, such accounts understood the EU as the interplay of national governments, and -unlike liberal intergovernmentalism -ignored the process of preference formation beneath the governments. Second, another legacy of cruder variants of intergovernmentalism is that member governments were seen as unitary actors.

This assumption, we believe, is a matter for empirical exploration and not a prior assumption.

Third, and also a legacy of early intergovernmentalist thinking, was the understanding of national governments as the "gatekeepers" of integration. In other words, as gatekeepers they are presumed to have a monopoly of contacts between national actors and the EU political system. In the heavily populated EU policy-making arena of the contemporary era this assumption looks highly problematic. These comments are not meant to position our paper in an anti-intergovernmentalist camp, for we are not seeking that kind of intellectual trench warfare. They are merely designed to reflect an emergent consensus on how to explore EU-member state relations in contemporary theorizing.

In exploring the study of EU-member state relations, one rather obvious point is worth making at the outset. Theoretical and empirical studies of EU-member state relations have tended to adopt a particular focus: they have either explored the impact of member states upon the EU, or have explored the impact of the EU upon the member states. However, there is a further, intermediate variant, which arises from the constructivist turn in political science: namely studies which regard the member state-EU relationship as an explicitly interactive one. Before examining these three approaches and the associated theoretical issues in more detail we simply make some assertions about why member states matter, and how.

Member states matter because:

• The "state of the European Union" at any one time, say after the Nice Treaty, is reflective of a balance of unifying (EU) and territorial forces/institutions. This balance represents an interplay of national and integrationist forces. They are not diametrically opposed forces in a zero-sum game but interact, for example to find creative policy solutions.

• Territoriality matters in the EU: it is the main organising principle. Identity, democracy and legitimacy tend to be located predominantly at the member state level (albeit normally with a layering of these within the state concerned). Similarly, the predominant form of institutional organisation within the EU is along national lines: whether, most obviously, in the Council hierarchy or in the distribution of commissioners or MEPs. The territoriality principle predominates in the institutions of policy-making, policy-implementation and of the judicial system.

• However, European integration has made the territoriality of politics more permeable, as have forces in the global economy, patterns of technological change and so on.

Thus, the importance of territoriality does not mean that the era of the Westphalian state has been "frozen" into the EU. On the contrary, European integration has gone hand-in-hand with a number of transformative changes to the state system: the erosion of national boundaries; some hollowing-out from below as a result of internal regionalism; the emergence of new forms of governance which have altered traditional boundaries between the public and the private (e.g. networked governance); and the growth of para-public agencies responsible for regulatory governance. European integration has not been the sole cause of these developments; indeed, in some cases it may not have been the cause at all. However, the key point is that changes within member states matter and are closely inter-linked with the development of the EU.

• Member states, i.e. not just governments, are key players in the politics of the European Union. Territorial-based interests are articulated upwards into EU arenas.

Empirical and analytical study of this process of upward articulation may be concerned with the role of actors, institutions and the attempt to project national policy preferences into the EU arena.

• Yet, at the same time, the EU is an important factor in member state politics. Its activities impinge upon political actors, institutions, policies and identities at this level.

This downwards direction of flow -often termed Europeanization -may be studied in isolation or as part of an iterative and interactive process.

• The dynamic interaction of member states and the EU is important in a number of specific ways.

-National governments and other actors must devise ways of making effective inputs into the political process at the supranational level (projection).

-

National governments and other actors must devise ways of incorporating EU business into their organisation of business at the national level (reception).

-For all actors at the national level -whether governmental, institutional, parties, interest groups or less formal parts of civil society -the EU creates a changing opportunity structure. New tactical and strategic opportunities are opened up in terms of "projection" for all these types of political actor.

-However, these new opportunities do not come without cost, for all these types of political actor are also subject to new constraints: policy commitments, legal obligations and so on.

-This interaction raises questions of logics: should the "logic" of political action in Brussels prevail or that of political action in the member state concerned? Does the EU act as a centripetal force, causing convergence in member states' patterns of governance and policies? Or is it compatible with distinctive national patterns? Do distinctive patterns remain?

-The types of actors confronted with these issues in their interaction with the EU are national governments (ministers and officials), parapublic agencies, national parliaments, subnational government, political parties, interest groups and civil society. Also affected, albeit in a slightly different way, are national courts, through the judicial process, and, in a more diffuse sense, public opinion and conceptions of identity.

-Finally, are the EU institutions the agents of national governments? Or are national government institutions becoming administrative arms of the EU's institutions, for instance as a growing number of monetary policy decisions are taken at supranational level? Similar questions may be asked of transnational political parties or transnational interest groups: do they remain the agents of their national constitutent member organisations?

These are amongst the key questions which the theoretical and empirical literatures on the relationship between the member states and the EU are concerned with. We turn initially to the theoretical literature and explore, first of all, how the "bottom-up" input of member states into the EU arena is captured before turning, secondly, to "top-down" approaches (Europeanization) and interactive ones (constructivism).

UNDERSTANDING MEMBER STATE-EU RELATIONS

Theorising the member states in the EU policy-making2

The theories of European integration, developed from the late 1950s onwards in the works of neo-functionalists and of intergovernmentalists, were for a long time a quasimonopoly of international relations specialists. There has been steady evolution since the 1970s, as European integration raised a range of questions -such as the legitimacy of public policies, the effectiveness of institutions, and the representation of actors -to which comparative politics and the comparative sociology of the state have been used to provide answers. The theoretical tool box has in this way been augmented by institutionalist approaches, and new governance approaches considering the EU as a polycentric polity in which notions of political authority and sovereignty have become elusive. These evolutions raise directly a question about the changing role of the member-state in integration theories [START_REF] Lequesne | The European Union: How to deal with a strange animal[END_REF].

The member state at the centre of EU bargaining Stanley Hoffmann, a student of Raymond Aron in Paris, was the investigator and for a long the sole representative of intergovernmentalism which sought to explain European integration by rehabilitating, in critical fashion, the diversity of Westphalian states. This position opposed that of the convergence of elites on which the neo-functionalists focused.

More than thirty years of regular publications made it possible for Stanley Hoffmann to repeat the main theoretical foundations of his approach [START_REF] Hoffmann | The European Sisyphus. Essays on Europe 1964-1994[END_REF].

• The EU is seen first of all as a venture in cooperation amongst states, which are rational actors and whose domestic functioning is governed by principles of authority and hierarchy. • In a context of generalised economic inter-dependence, the EU constitutes a more profound form of "international regime" -defined as a set of common norms, institutions and policies allowing those states to manage more efficiently specific issue areas such as trade, agriculture or the environment [START_REF] Hoffmann | Reflection on the nation-state in Western Europe today[END_REF][START_REF] Levy | The study of international regimes[END_REF].

• The resulting "pooled sovereignty" does not lead to a diminution of the role of the states, but on the contrary to a strengthening of that role, encouraging their adaptation to constraints imposed by the international environment.

• The creation of one regime does not necessarily lead to the creation of others by an automatic spill-over effect, as the neofunctionalists supposed at the beginning of their work.

For Hoffmann, the expansion of the European political agenda is possible only at the cost of conflict and compromise among the governments of the EU member states. It happened more easily in some domains, such as the economy and welfare, than in others, such as foreign policy and defence, in which member governments prefer the security of their independence to the uncertainty of cooperation which they could not be sure of controlling.

However, the attention that Hoffmann has always paid the EU member states' domestic policies has never made him a "pure realist" asserting, like Kenneth Waltz for ins tance [START_REF] Waltz | Theory of International Politics[END_REF], that a state's national interest derives solely from its position in the international system. This concern to take account of the domestic-foreign relationship is also found by other political scientists like Simon Bulmer, not an intergovermentalist but one of the first analysts to make explicit the need to investigate the domestic context in order to understand the political processes at the EU level [START_REF] Bulmer | Domestic politics and EC policy-making[END_REF]. The domestic-EU relationship is also present in the works of American political scientists who have revisited the intergovernmental paradigm from the mid-eighties onwards.

While variants of intergovernmentalism were above all the work of an American IR theorist, it was a British historian who contributed to their spread in Europe. Alan Milward considered that the heavy interdependence of markets in coal, agriculture and trade left European welfare states after 1945 with hardly an alternative to organising themselves collectively to bestow welfare policies on their citizens [START_REF] Milward | The European Rescue of the Nation-State[END_REF]. Refuting the thesis that states renounced part of their sovereignty in creating common EU institutions, Milward asserted, on the contrary, that this was a means for each of them to recover individually. A static conception of national sovereignty nevertheless led Milward, in analysing the formation of the European Communities, to consider member states either as "guardians of the temple" (the thesis that he is defending) or as "abdicators" (the thesis that he refutes). However, it is arguably more interesting to get away from these idealised categories and consider intermediate models [START_REF] Lequesne | Les Etats membres de l'Union européenne. De la pertinence d'une approche institutionnelle[END_REF].

The revival of intergovernmentalist approaches also came about through the theory of rational choice, which has gained substantial ground in American political science since the 1980s. Starting from an hypothesis that there are states desiring to cut transaction costs in an open economy, rational choice theorists consider European integration above all as a collective action whose aim, for each state, is to optimise gains in the sense of Pareto optimality. Geoffrey Garrett's work on the establishment of the single market is a good example, although he takes care not to reduce collective action within the EU to the economic and functional dimension alone (Garrett, 1993). He insists on also taking into account member states' political preferences, which are in fact the central governments' domestic policy preferences. However, he did not explore the relationship between states' political preferences and demands from the societies composing them.

It was out of concern to restore the relationship between state and society that Andrew Moravcsik devised in the early 1990s another approach, described as "liberal intergovernmentalism". This has become an established reference in the literature and cannot be ignored by anyone interested in European integration [START_REF] Moravcsik | The Choice for Europe: Social Purpose and State Power from Messina to Maastricht[END_REF]. In pursuit of the ambitious project of building a theory of European integration, as American academics are tempted to do in a professional world where "having one's theory" looks good for the career, Moravcsik starts from three research postulates:

• The state is a rational actor in Europe.

• Power in the EU is the result of bargaining amongst states.

• Liberal theory is needed to explain the formation of national preferences within the state.

The first two hypotheses belong to the tradition of realism in international relations.

They correspond with those that Stanley Hoffmann was able to test in his own works. Three limitations can be emphasised. In seeing the EU member states through the prism of central governments alone, Moravcsik neglects their internal diversity (two-party coalitions, relations between central executives and regional authorities, rivalry amongst agencies and bureaucracies), though this diversity is indispensable for understanding their different positions with regard to the EU. Next, assuming that the EU is an arena where large member states exercise power, Moravcsik simplifies the decision-making games considerably. But it is not at all certain that the convergence of domestic policy preferences in Germany, France and the UK on the single market question carried more weight in the adoption of the Single European Act than the doubling of structural funds desired by the Mediterranean States and Ireland and institutional reforms to which the Benelux countries were very attached [START_REF] Moravcsik | The Choice for Europe: Social Purpose and State Power from Messina to Maastricht[END_REF]. Lastly, Moravcsik sees in EU institutions only agencies created by the member states with the purpose of increasing the initiative and influence of national governments, although they are also organisations with autonomous ideas and interests in relation to the states that have set them up.

The formation of national preferences constitutes the most original hypothesis in relation to the realist tradition of IR. While Moravcsik sees bargaining among states as a confrontation of national interests, he also sees in those interests demands addressed by domestic societal actors to 'their' national government. His assumption that societal principals delegate power (or otherwise constrain) governmental agents may be criticised as too simplistic. It presupposes that the member states remain the sole setting for representation in Europe, and that national societal actors therefore have a very low capacity for organising themselves transnationally. In developing this model Moravcsik was influenced by Robert Putnam's two-level game approach: an analytical framework which has its own independent value for understanding the role of member governments in EU negotiations [START_REF] Putnam | Diplomacy and domestic politics: The logic of two-level games[END_REF].

While liberal intergovernmentalism in particular, and the intergovernmentalist approaches in general, can prove to be theoretical frameworks usable for the analysis of "grand bargains" (the Treaty of Rome, the European Monetary Union, the Treaty of Nice, etc…), or the analysis of those European policies that remain very much under the control of central executives (like the Common Foreign and Security Policy), it is fairly easy to discern the limitations inherent in the monist bias underlying them. That bias prevents understanding the political construction of the EU on the basis of configurations of interests and ideas which are certainly expressed by central governments but also, increasingly, by supranational institutions, sub-national regions, non-governmental actors, etc…

The member state in institutionalist approaches

Since the mid-1980s a debate has arisen within EU theoretical debates on the need to go beyond state-centric approaches to the analysis of a multi-level polity. The need to understand the configurations of large numbers of actors has led to a comeback for neofunctionalism. It has also been reflected in new theoretical approaches borrowing more from institutionalist analysis. The role of the member state becomes less exclusive in these approaches although it is far from being totally marginalised.

Neo-functionalism, which had been declining since the 1970s, had a new surge of strength at the time of the Single European Market. Although they take care to distinguish their analysis from that of Haas and Lindberg, Wayne Sandholtz and John Zysman [START_REF] Sandholtz | Recasting the European bargain[END_REF], or Wayne Sandholtz and Alec Stone Sweet (Sandholtz and Stone Sweet, 1997) argue that a series of transnational alliances between economic actors, conscious of the changes imposed by globalisation, explains the development of the EU's supranational institutions. Regarding the role of the member states, these authors do not deny at all the importance of convergence between governments as a condition for institutionalisation. However, they give most importance to the formation of transnational interests as the stimulus for institutional change. In this sense, they are close to what the "original" neo-functionalists tried to formulate in their general theory of European integration. Mark Pollack is another author who tried to make explicit the institutional links between the national governments and the supranational institutions. Focusing his work on the question of delegation of authority, from a rationalist perspective Pollack considers that the supranational institutions are "agents" created by "principals" (the member states) to reduce the transaction costs in their negotiations [START_REF] Mark | Delegation, agency and agenda setting in the European Community[END_REF].

It was from the 1980s that an analytical trend called "new institutionalism" developed within American political science, around two simple assertions [START_REF] March | Rediscovering Institutions: The Organisational Basis of Politics[END_REF].

• Institutions are more than the reflections of underlying social forces.

• Institutions do more than produce a neutral arena for political interaction.

New institutionalism, which is more a catalogue of research hypotheses than an analytical model, has given birth to several variants including historical institutionalism (Steinmo, Thelen and Longstreth, 1992), which was quickly taken up by some analysts of European integration (see Schneider and Aspinwall, 2001). [START_REF] Bulmer | Four faces of European Union governance: A new institutionalist research agenda[END_REF] and [START_REF] Pierson | The path to European integration. A historical institutionalist analysis[END_REF] explain that the EU can only be analysed in relation to institutions which are the contemporary receptacles of a historical process. They give institutions quite a broad meaning including formal structures, norms, and policies, as well as informal ones. From this approach, aiming to rehabilitate the effects of structure, two methodological implications emerge for the study of the EU.

• Politics at the EU level is no longer seen as a series of strategic decisions made by national governments but as a "path dependent" process with a series of critical situations and unforeseen consequences. • Institutions at supranational and national levels should no longer be regarded only as instruments in the service of outside pressures but as structures capable of integrating experiences and norms over the course of time.

Politics and policies are seen in this way as operating on the basis of an existing stock of social capital reflected particularly in member states' institutions as well as in supranational ones (Amstrong and Bulmer, 1996a).

The return of federalist studies is another institutionalist development which contributed to the rehabilitation of the member state in the analysis of European integration. Alberta Sbragia restored credit to the federalist approach of the EU in the 1990s (Sbragia, 1992). Among the factors making comparative federalism relevant, Sbragia mentioned the fact that within the EU the continuing problem of balance between territorial interests and functional interests is at issue. This view offers useful trails for researchers who wish to conceptualise the two dynamics -at Community and inter-state levels -which have presided over the formation of the EU since its beginning [START_REF] Quermonne | Le système politique de l'Union européenne[END_REF]. Similarly it makes it possible to develop theories about the dialectical relationship between a de-territorialised political project and interests that remain firmly rooted in member states' territories, as one can see empirically in studying EU policies and politics [START_REF] Lequesne | L'Europe bleue. A quoi sert une politique communautaire de la pêche[END_REF].

The fact that federal political systems have tended in recent decades to develop from their original dualist form towards an ever increasing overlap between the levels of government ("cooperative federalism") is also a pertinent element for analysing the ongoing obligation to find consensus between the different member states' institutions at one level, and the EU institutions at the other level [START_REF] Scharpf | The joint decision trap: L essons from German federalism and European integration[END_REF][START_REF] Croisat | L'Europe et le fédéralisme[END_REF].

Cooperative federalism also makes it possible to reflect on the exercise of democracy in political systems which tend to attach importance to interaction among executive authorities (ministers, specialised committees of civil servants) at the expense of control by parliaments and societies. In the end, works inspired by federalism have the advantage of studying not only EU-member state relations as a process but also as a "political order". Nevertheless, they tend to remain confined to "intergovernmentalism" (in the comparative politics sense) and neglect the links between politics and societies.

The member states in the new governance approaches

The 1990s have been marked by a quite strong convergence between IR theorists and theorists of the state that analysis of the state should no longer necessarily start from the hypothesis of its withdrawal in favour of social self-government. The state should rather be analysed as the interaction of a large number of governing actors who are not all state or even public actors [START_REF] Leca | La gouvernance de la France sous la V e République. Une perspective de sociologie comparative[END_REF]. These authors, having to describe the new forms of government that this movement implies, have often resorted to the notion of governance.

While this notion was quickly taken up by the EU institutions themselves (European Commission, 2001) to push for the pluralist engagement of civil society in the running of politics, its primary sense is analytical. James Rosenau, for instance, resorts to governance to describe how international politics concerns not only the activities of states but also of informal, non-governmental mechanisms whereby those persons and organisations move ahead, satisfy their needs and pursue their wants [START_REF] Rosenau | Governance, order and change in world politics[END_REF]. Similarly, Renate Mayntz uses the concept of governance to stress that the dynamics of Western societies tends to give ever greater autonomy to social groups, and that analysis of the state therefore implies identifying modes of horizontal coordination among sub-systems more than a machinery of commanding authority and vertical administration (Mayntz,1993).

As the EU does not allow obvious manifestation of the autonomy of a particular "ruler", and does not recognise a clearly defined border between "public" and "private" actors, it is quite understandable that some researchers, wanting to distance themselves from statecentric thinking, should have chosen to analyse the EU as a governance model [START_REF] Marks | European integration from the 1980s[END_REF][START_REF] Marks | Governance in the European Union[END_REF]Armstrong and Bulmer, 1998;[START_REF] Kohler-Koch | Catching up with change: The transformation of governance in the European Union[END_REF]. In these works, the member state is no longer in a situation of monopoly or of hierarchical superiority.

EU politics and policies are the results of interactions between the Commission, the member states, regions and interest groups.

Studies of EU governance raise questions about the conditions for the emergence of an EU political agenda. This term is intended to describe a situation where national actors possess overall mastery of identifying policy problems, and above all their resolution, to a situation where in an ever increasing number of fields this process of problem-definition is transferred to the European level (Muller,1996). Examination of the debates and controversies linked to the definition of an EU political agenda leads to a series of observations on the specific features of actors involved in the European political system. At the member state level, specialised experts (civil servants of national ministries, interest group representatives) exercise more power than in the "traditional" European state.

Conflicts therefore centre less around problems of representation than around control of expertise [START_REF] Radaelli | Technocracy in the European Union[END_REF].

Studies of EU governance made progress possible in the understanding of the modus operandi of EU decision making. The principal observation is that, in the absence of a vertical axis of strong authority within the EU, forms of decision-making are fluid, with little hierarchy. Those forms, often comprehended within the concept of policy networks, are characterised by pluralist configurations of actors (including national officials, Commission officials, representatives of interest groups, etc…) which do not conform to a single institutional model but, on the contrary, tend to become differentiated through the gradual emergence of internal rules of the game in each sector. Reproducing the type-casting used for the study of policy making in the UK (Marsh and Rhodes, 1992), writers distinguished different types of policy networks at the EU level according to their stability and the elements underlying transactions by their members (Richardson, in Kassim and Menon, 1996).

Member state actors are not excluded from the policy networks. They share the transactions with other member state actors and with supranational actors. Moreover, policy networks make negotiation the dominant mode of political transaction at the European level. This permanence of negotiation is strengthened by the fact that the main EU policies are regulatory ones [START_REF] Majone | La Communauté européenne: un Etat régulateur[END_REF]. Regulatory policies encourage actors subjected to them (especially national administrations and interest groups) to negotiate with the EU Commission the precise obligations involved.

Studies of EU governance also make it possible to redefine the relationships between European integration and democracy. Through the diffuse nature of the EU polity comes the question of democratic accountability. "Who is accountable for what?" is a frequent question in the national debates on the EU [START_REF] Jachtenfuchs | Regieren im dynamischen Mehrebenensystem[END_REF]. In the debate about the EU's evolving constitution this theme emerges as consideration of whether there should be a listing of the EU's competences. These issues and debates give rise to comparison with federal states or with states -like France or the United Kingdom -which have been through the experience of decentralisation or devolution.

Studies on EU governance, lastly, make it possible to deal with the problem of the influence of the EU over national politics and policies. Which brings us to Europeanization.

The impact of European integration on member states: Europeanization

Exploring the impact of integration upon the member states (and sometimes upon applicants or near-neighbours of the EU) is generally termed Europeanization (see below).

However, there are three other developments in the literature which deserve prior exploration because they provide an important context for the Europeanization literature. They relate to three propositions:

• that integration strengthens the state;

• that integration creates a new multi-level politics thereby recalibrating how domestic actors respond to integration; and • that the EU has transformed governance.

In a 1994 paper Andrew Moravcsik developed the first of these arguments, namely that the European Community strengthens the nation state [START_REF] Moravcsik | Why the European community strengthens the state: Domestic politics and international cooperation[END_REF]. This argument chimed with his own "bottom-up" liberal intergovernmentalist analysis of integration; the link being provided by the centrality of "the state". Little further exploration of this argument has been undertaken. But just as Moravcsik's theoretical interpretation of integration was contested, so too was this paper. One of his "adversaries" on integration theory, Wayne Sandholtz, argued for an alternative interpretation of the impact of integration upon member states [START_REF] Sandholtz | Membership matters: Limits of the functional approach to European i nstitutions[END_REF].

He suggested that integration could create new "options for domestic actors in their choice of allies and arenas" (multi-level politics), and induce changes in domestic institutions and policies. What Sandholtz was making clear by "multi-level politics" was much the same point as made by Gary Marks and his collaborators (e.g. [START_REF] Marks | European integration from the 1980s[END_REF], namely that national governments neither represent the sole objects of integration nor the exclusive link between national politics and the EU (Sandholtz, 1996: 412). Essentially he was arguing that domestic actors -governmental or societal -recalibrate their goals as a result of EU membership. His concern was not with domestic change per se but with reinforcing a non state-centred understanding of integration. However, he went further and argued that domestic actors could exploit the supranational situation to secure domestic change.

Predating more recent analyses he pointed to the French and Italian governments exploiting the requirements of t he European Monetary System and European Monetary Union respectively to secure domestic policy reform (Sandholtz, 1996: 423-6).

The "transformation of governance" argument is especially associated with Beate Kohler-Koch and her collaborators. Her argument is that integration has not only shifted the distribution of power between multiple levels of authority but has also shifted the boundary between the public and private spheres (Kohler-Koch, 1996: 360). The character of the state -its institutional structures and political processes -is transformed as part of this process (also see Jachtenfuchs and Kohler-Koch, 1996: 22-3;Kohler-Koch and Eising, 2000): quite the reverse of Moravcsik's argument.

The three propositions outlined above may be seen as precursors to the literature explicitly termed Europeanization. This literature is at an earlier stage of conceptual development than that relating to the impact of member states on the EU. For instance, there is no theoretical approach elaborated to the same degree as Moravcsik's liberal intergovernmentalism (1993;[START_REF] Moravcsik | The Choice for Europe: Social Purpose and State Power from Messina to Maastricht[END_REF]. The current "state of the art" in the literature is proceeding cautiously from using Europeanization as a loose background concept to one which is more systematised in nature (see Radaelli, 2000 for discussion). However, we can at least identify a number of common points of departure which have arisen since Robert Ladrech's early exploration of Europeanization in France [START_REF] Ladrech | Europeanization of domestic politics and institutions: The c ase of France[END_REF].

• First, there is no "theory" of Europeanization.

• Second, Europeanization is normally used to look at the impact of the EU on member states: something which might better be termed "EU-ization", were it not for this being a dreadful word. However, with the EU's growing importance as a facilitating arena for the exchange of policy ideas and practice, such as through the Lisbon process in the employment arena, the exact role of the EU -as source or facilitator of change -is being placed in question.

• Third, there seems little point using Europeanization as a synonym for European integration. Thus, where European integration is concerned with political and policy development at the supranational level, Europeanization is concerned with the consequences of this process for (chiefly) the member states.

• Fourth, these consequences are a matter of establishing whether the "fit" between EU circumstances and their domestic counterparts necessitates domestic adjustment: whether of institutions or policies and, consequentially, of the relevant political actors.

• Fifth, unless the actors within member states are entirely passive in their response to Europeanisation, they are likely to respond through making inputs into the integration or policy-making processes. Hence there is a clear link between the literatures discussed in the t wo parts of this paper. However, each literature tends to concentrate on a different direction of flow in the EU policy "cycle": bottom-up or topdown. How may these different understandings of Europeanization be compared and contrasted? Two features are prominent:

Beyond these observations a broad aspiration in the development of Europeanization

• the concern with adjustment processes is ever-present;

• and institutionalist analysis is very prominent.

But the empirical analysis of Europeanization may usefully be distinguished between impact on institutional structures, on policy, on political forces/actors, and on political economy.

Institutional structures

Tanja Börzel utilises an explicitly institutionalist approach to understanding how the German and Spanish subnational levels of government coped with the need to adjust to integration, and to explain divergent practice between the two cases. Thus she offers three propositions on how domestic institutions matter.

• They determine the distribution of resources among domestic actors.

• They determine the degree to which Europeanization changes the distribution of resources among domestic actors. • They strongly influence the way in which domestic actors respond to the misfit between European and domestic institutions (Börzel, 1999: 577-80).

These propositions offer useful insights into exploring a number of other empirical phenomena that have been linked to the impact of the EU on member states, such as the following:

• the strengthening of national governments vis-à-vis national parliaments (Rometsch and Wessels, 1996b: 334-41).

• the differential responses of national governments across the EU, when confronted with the common challenge of engaging in EU policy-making [START_REF] Rometsch | Conclusion: European Union and national institutions[END_REF]Wessels, Maurer and Mittag, 2001 forthcoming;

Bulmer and Burch, 2001);

• the differential adjustments within governments (i.e. different responses of ministries, e.g. [START_REF] Bulmer | The europeanisation of British central government[END_REF] or even within ministries, e.g. the strengthening of the environmental functions within the traditionally more multifunctional (despite the name) UK Department of the Environment [START_REF] Jordan | The Europeanisation of UK environmental policy, 1970-2000: A departmental perspective[END_REF][START_REF] Smith | Cultural aspects of europeanisation: The case of the Scottish office[END_REF];

In each of these three cases adjusting to Europe arises from some form of "misfit" between the broad institutional arrangements at EU level and their counterparts at domestic level. But if the above illustrations are concerned with institutional adaptation, what, then, of policy adaptation?

Policies

In exploring the impact of Europeanisation upon domestic policy an immediate problem arises: is it as easy to isolate the EU as an independent variable as when exploring institutional adaptation? Air transport liberalisation in EU member states may be taken as an example: did it occur as a consequence of global industry forces including US de-regulation in 1978; did it occur because of Europeanisation -the impact of three EU packages of liberalisation measures (1987/1990/1992); or did it occur because of distinct domestic moves? In the UK case domestic (and bilateral) policy reform pre-dated and informed the EU-level policy, so Europeanisation subsequently represented much less of a misfit than, say, for Greece, which had not liberalised domestically. But both UK and European liberalisation were influenced to some degree by global trends in the industry. This problem of attributing causality or of isolating EU-effects is common to many market-liberalising cases (e.g. see Schneider, 2001 on telecommunications). The danger is one of attributing change to Europeanisation while under-emphasising the global pressures against which the supranational level might be designed to offer some protection.

The air transport case illustrates another aspect of how member governments cope with the EU's impact. Do they try to export their policy models to the EU, sometimes termed "uploading", or do they act in a more passive manner, "downloading", whereby they have to bear larger adjustment costs. The UK was relatively weak at the "uploading" of policy models to the EU level until the advent of the single market project and this situation reflected the contested domestic context of European policy. Persistent "downloading" may lead to three outcomes: non-implementation of policy; major domestic adjustment costs; and, in extreme circumstances an accumulating performance crisis (Risse, Cowles and Caporaso, 2001: 8-9). The uploading strategy highlights again that Europeanization is part of an ongoing cycle of interactions between the EU and the member states. Strategies for successful uploading include agenda-setting in EU arenas, coalition-building with partner states and so on.

Risse, [START_REF] Risse | Europeanization and Domestic Change: Introduction[END_REF] have devoted particular effort to explaining the circumstances under which Europeanization can bring about change in domestic structures.

They identify five intervening categories of domestic variable to explain adjustment: multiple veto points; mediating formal institutions; political and organizational cultures; the differential empowerment of actors; and learning. These five categories inform the case-study analyses in their anthology. Like many other observers they do not regard adjustment as necessarily bringing about harmonization. As Les Metcalfe has pointed out (1996: 48-51), integration has two variants: a hierarchical "amalgamation" trajectory (harmonization) and a "pluralist" trajectory (policy co-ordination or even competition among rules). These two trajectories impose quite different forms of adjustment cost for domestic policies and structures.

Political actors

The literature on the Europeanization of political actors is empirically thinner on the ground and less developed analytically. [START_REF] Hix | Introduction: European integration and national political systems[END_REF] suggest some useful starting points in identifying the constraints and options that Europeanization can present at the domestic level. In particular their options category suggests:

the establishment of a higher level of governance institutions provides new opportunities to exit from domestic constraints, either to promote certain policies, or to veto others, or to secure informational advantages (Hix and Goetz, 2000: 10).

The possibility is highlighted for strategic responses by domestic political actors to the new European institutional opportunity structure. However, the development of such ideas, and their empirical investigation is rather limited hitherto.

The EU and member states: constructivist approaches

The distance between the Europeanization literature and a constructivist approach to understanding EU-member state relations is not too great. Constructivism shares some common ground with institutionalist approaches. And the Europeanization literature likewise tends to emphasise the interactive nature of the relationship. What, then, are the key insights that constructivism can add to the study of the relationship?

First, it can reveal that interests are socially constructed as well as (or even instead of) the product of material interests. This position is clearly at odds with a liberal intergovernmentalist view of member state-EU relations. It can explore whether national participants in the EU policy process are socialised into different values and behaviour that might impact upon their presentation of national policy. Social learning by national policymakers is brought into the picture (see [START_REF] Checkel | Social construction and integration[END_REF].

Second, it also regards political space and territorial units as socially constructed.

Hence it can capture the greater fluidity of European governance associated with multi-level governance, whereby the nation state is no longer automatically the gatekeeper between the EU and subnational government [START_REF] Christiansen | Reconstructing European space: From territorial space to multilevel governance[END_REF]. From this perspective the nation state concept is interrogated.

Third, the empirical concern of constructivism shifts towards the more cultural end of an institutionalist spectrum: to norms, values and identities. Norms and values may be uploaded or downloaded as much as more concrete policy preferences. Moreover, national identity may be understood to be constructed in interaction with the EU, thereby breaking another of the traditional tenets of international relations (see, for instance, Marcussen et. al., 1999;Risse, 2001).

Fourth, it opens up new research approaches: ones which may include the role of discourse as a means of understanding member states' diplomacy in the EU, whether generally or on a specific issue [START_REF] Diez | Speaking 'Europe': The politics of integration discourse[END_REF][START_REF] Parsons | Domestic interests, ideas and integration: The French case[END_REF]. Although some applications of discourse analysis are quite rarefied, others insert it alongside more institutionally-grounded understandings of Europeanization, such as in the work of Vivien [START_REF] Schmidt | Europeanization and the dynamics and mechanics of economic policy adjustment[END_REF].

These constructivist insights do come at some cost. Most notably, the departure from the established traditions of political science, such as positivist methodology, may be a step too far for some. And for the more casual student of EU-member state relations this departure means a loss of trusted reference-points and no clear set of replacements.

EMPIRICAL STUDIES OF MEMBER STATE-EU RELATIONS

A key question which immediately arises when turning to empirical studies is whether they can be placed clearly in the categories identified above. The answer is "no", and for two principal reasons. First, it is clear -without buying into a constructivist interpretation -that the empirical relationship between the EU and member states is interactive. National governments, for instance, are having to develop increasingly extensive methods of making European policy, e.g. as justice and home affairs or defence policy have come onto the agenda, but these challenges arise from a Europeanization effect. Second, empirical studies of the relationship have not always been clear regarding their analytical focus. Thus, specialists on sub-national government or on legislative studies have detected that European integration has impinged on their field of study but have not made explicit whether their analytical focus is on, say, parliamentary adaptation to integration or on the efforts of national parliaments to increase their effectiveness in participating in EU policy-making. Their research agenda is either strictly empirical or concerned with issue-specific debates. A third complicating factor is where literature is misclassified. For instance, Bulmer and Paterson's study of European policy-making in West Germany [START_REF] Bulmer | The Federal Republic of Germany and the European Community[END_REF], a study based on Bulmer's ("inside-out") domestic politics model has been cited as an illustration of the Europeanization literature (Goetz and Hix, 2000: 17;Risse, Cowles and Caporaso, 2001: 3).

As a first step, therefore, we simply i dentify some illustrative studies of the relationship of member states and the EU before trying to navigate a way through the thicket of empirical studies. Several books have been devoted to the EU decision-making process in one country [START_REF] Bulmer | The Federal Republic of Germany and the European Community[END_REF]George, 1992;[START_REF] Guyomarch | France in the European Union[END_REF][START_REF] Lequesne | Comment se fait la politique européenne de la France[END_REF]also see Wright, 1996). More broadly-based studies of relations between individual member states and the EU have been especially concerned with the case of Germany, particular its power in the EU (Katzenstein, 1997;[START_REF] Bulmer | Germany's European Diplomacy: Shaping the Regional Milieu[END_REF][START_REF] Anderson | German Unification and the Union of Europe[END_REF]). In addition several edited collections have sought comprehensive coverage of all, or nearly all, member states [START_REF] Rideau | Les Etats membres de l'Union européenne. Adaptations, mutations, résistances[END_REF]Rometsch and Wessels 1996a;Twitchett 1981). A particular emphasis has been placed on the role of national governments in EU decision-making (Kassim, Peters and Wright, 2000;Pappas, 1995;[START_REF] Wallace | National Governments and the European Community[END_REF].

Other more specific domains of national politics have also been covered comparatively:

notably parliaments (Norton, 1996;Laursen and Pappas, 1995) and sub-national government (e.g. Jeffery, 1997;Jones and Keating, 1995). The institutional changes and the enlargements of the EU have also inserted into the academic debate new questions on the adaptation of small member states (and sometimes third states, like Norway and Switzerland) to the EU [START_REF] Hanf | Small states and the europeanization of public policy[END_REF][START_REF] Arter | Small state influence within the EU[END_REF]. There is a much more limited literature on the implementation of Community law in the various member states (Siedentopf and Ziller, 1988;also see Pappas, 1995). Beyond these primarily book-length studies there is a massive array of shorter pieces but they are often confined to circumstances in one member state and cannot be reviewed here (but see Hix and Goetz, 2001;[START_REF] Radaelli | The Europeanization of public policy: Notes on t heory, methods and the challenge of empirical research[END_REF] for other reviews).

Of the above studies only two -those by [START_REF] Rometsch | Conclusion: European Union and national institutions[END_REF] and [START_REF] Hanf | Small states and the europeanization of public policy[END_REF] deal with Europeanization by virtue of having a substantial explicit concern with the effects of integration upon the member states rather than vice versa.

Indeed, attempts to explore Europeanization empirically have been rather haphazard in nature or lacking in an explanatory framework (Andersen and Eliassen, 1993;[START_REF] Mény | Adjusting to Europe: The Impact of the European Union on National Institutions and Policies[END_REF]. There have been relatively few systematic efforts to capture the phenomenon conceptually. The most useful, substantial studies have appeared recently (West European Politics, 2000;[START_REF] Risse | Europeanization and Domestic Change: Introduction[END_REF]. A small number of shorter, comparative papers also merit attention for raising broader issues in the context of an empirical account (e.g. [START_REF] Börzel | Towards convergence in Europe? Institutional adaptation to europeanization in Germany and Spain[END_REF]Bulmer and Burch 2001;Harmsen 2000).

From this corpus of work we try to identify some themes which address, respectively, the way member states seek to make an impact on the EU and its policy process, and the impact of the EU on the member states.

Effectiveness and power

Arguably the most important issue which has been raised in studies of member states' European policy and policy-making has been that of effectiveness and power. As indicated above, there are many empirical studies of domestic policy-making. But does domestic effectiveness make a difference at the EU level? This issue was brought into focus particularly well in a study by Vincent Wright:

...the effectiveness of a country's domestic EU coordinating capacity must be judged according to the issue, the policy type, the policy requirements and the policy objectives. Merely to examine the machinery of co-ordination is to confuse the means and the outcomes (1996: 165).

Wright's comments were important in that they highlighted that domestic co-ordination is no guarantee of being an effective negotiator at EU level. It was a sentiment sometimes articulated off the record by British officials in the latter years of the Conservative government in the mid-1990s: there was no use having a Rolls Royce machinery with a lunatic at the wheel! The point is that there is more than one way to have an impact at EU level and effective internal co-ordination is no guarantee for securing such an outcome. As Hussein Kassim has pointed out: member states have very different co-ordination ambitions. Some have far-reaching, strategic, and directive conceptions, and aim to construct an agreed position on every issue and to ensure coherent presentation by all national representatives at every stage of the EU policy process. Others have more modest ambitions that may be substantive -limited to particular policy types or issues -or proceduralfiltering out policies that conflict with higher aims …. These ambitions imply very different co-ordination strategies (Kassim, 2000: 243).

The UK, Denmark and France are seen as illustrative of the former category, whereas

Germany is most clearly in the latter camp along with other states with dispersed domestic authority such as Belgium. That being in the former category is no guarantee of success at shaping EU policy outcomes was most obviously demonstrated with the UK government's counter-productive policy of non-co-operation over Europe in 1996: a response to the ban on British beef exports owing to the BSE crisis (see Westlake, 1997). And it has been argued

that Germany has been able to have a major impact on the overall pattern of the integration process [START_REF] Bulmer | Shaping the rules? The constitutive politics of the EU and German power[END_REF] even if this influence has not reduced the German adjustment costs of Europeanization (Cowles and Risse, 2001: 224). A possible explanation for this apparent discrepancy in the effectiveness of the British and German systems is that highly coordinated systems assist with the articulation of more detailed policy issues, whereas less coordinated systems may be better at articulating policy ideas. It may be, however, that Germany is a special case on account of the centrality of the "German problem" to European integration.

The implications of all this for the relative power and influence of member states in the EU remains virtually unexplored.

A similar kind of debate to that on the effectiveness of national governments has arisen regarding the regions in European integration. The original debate between the protagonists of regional empowerment, on the one hand, and those arguing that national governments retain control, on the other, has moved into more nuanced territory (for a review, see [START_REF] Jeffery | Sub-national mobilization and European integration[END_REF].

National institutions and the EU: the linkage issue

As Klaus Goetz has written: "The majority of contributions to the Europeanisation debate focus on linkage issues, notably the institutional arrangements that link national executives and EU authorities and the institutional practices that have evolved at the national level to support national -EU connections" (Goetz, 2000: 212). Here we move to empirical issues at the intersection of "inside-out" and "outside-in" approaches.

Linkage studies look predominantly at the structural adaptation of central bureaucracies to the EU policy-making and at coordination practices. They put the focus more on the national level than on the EU level, arguing that national political and administrative opportunities remain important sources of differentiation vis-à-vis the EU. In this respect, there is a gap between the policy-oriented literature which strongly supports a convergence of national policies and the literature devoted to institutions which supports the differentiation of national practice. Some authors, belonging to the institutionalists, have nevertheless spoken of the fusion of the national executives at the EU level [START_REF] Rometsch | Conclusion: European Union and national institutions[END_REF]. The "fusion thesis" by virtue of its name is over-suggestive of convergence even if it is very true that the EU does produce some similar effects on institutions in every member state; for instance, a de-hierarchisation of the administrative processes among the executives [START_REF] Kassim | Conclusion -The national co-ordination of EU policy: Confronting the challenge[END_REF], or a stronger obligation for the executives to inform the national parliaments on foreign issues [START_REF] Rideau | Les Etats membres de l'Union européenne. Adaptations, mutations, résistances[END_REF]. More interesting is when studies conclude empirically on the existence of a dialectic between the process of differentiation and the process of convergence at the national level. Bulmer and Burch wrote for instance: "What is remarkable about the British central government adaptation to the EU […] is the extent to which, while change has been substantial, it has been more or less wholly in keeping with British traditions" (Bulmer and Burch, 2001).

If linkage studies put their focus on the national level, they have said less about the behaviour of national executives inside the EU institutions. There is a lack of literature on the negotiation of national executives inside the EU Council of Ministers (Hayes-Renshaw, [START_REF] Hayes-Renshaw | The Council of Ministers[END_REF][START_REF] Sherrington | The Council of Ministers: Political Authority in the European Union[END_REF]. There is also very little on the communication channels between the capitals and their respective permanent representations in Brussels (Hayes Renshaw, [START_REF] Hayes-Renshaw | The permanent representations of the member states to the European Communities[END_REF]Beyers and Dierickx,1997) or on the roles of national officials in the EU institutions, including the Commission [START_REF] Stevens | Brussels Bureaucrats? The Administration of the European Union[END_REF].

EMPIRICAL STUDIES OF EUROPEANIZATION

As noted earlier, a small number of edited collections have suggested a systematic attempt to explore processes of adjustment but without establishing a convincing framework (e.g. Andersen and Eliassen, 1993;[START_REF] Mény | Adjusting to Europe: The Impact of the European Union on National Institutions and Policies[END_REF]. Andersen and

Eliassen's collection sought to explain "Europeification" by emphasizing a focus on the totality of the European Community and national institutions. But this definition did not make clear whether a bottom-up or a top-down understanding was assumed. Many of the policy case studies would have fitted a study on EU policy-making or on sectoral integration, so the actual contribution of Europeification was unclear. Only the contribution by Yasemin Soysal (1993) suggested a clearer definition.

The "Europeification" process … is one of gradual transnationalization and standardization through consensual organizational activity, generating a common discourse, if not necessarily common action, justified and propounded by a network of national/international experts, bureaucrats, academicians, and public interests (Soysal, 1993: 179).

She further suggested that the (sociological institutionalist) work by [START_REF] Dimaggio | The iron cage revisited: Institutionalized isomorphism and collective rationality in organizational fields[END_REF] might be deployed to identify the dynamics behind this process, namely coercion, imitation and normative processes. This work by DiMaggio and Powell has also been influential in the subsequent thinking of Claudio [START_REF] Radaelli | The Europeanization of public policy: Notes on t heory, methods and the challenge of empirical research[END_REF] on Europeanization.

The collection by [START_REF] Mény | Adjusting to Europe: The Impact of the European Union on National Institutions and Policies[END_REF] brought together contributions largely on member state and policy adjustment; they presented useful empirical studies but did not work to a common conceptual or theoretical understanding of adjustment. The result is rather similar in other collections within a series looking at the state and the European Union (Kassim and Menon, 1996;Howarth and Menon, 1997;Forder and Menon, 1998;Hine and Kassim, 1998). The distinction is that the empirical focus is more concentrated: on industrial, defence, macroeconomic, and social policy respectively.

A rather more analytical approach to member state adaptation is offered by Wolfgang Wessels in his contribution to The European Union and Member States (Rometsch and Wessels, 1996a). He suggested that member states would react and adapt in three steps (Wessels, 1996: 35-6).

• Europeanization would be the first step. A growing number of national actors would respond to the impact of the EU by seeking "voice": an improved means of participation. National actors would be affected in a similar way, but Europeanization was seen as only the first of three steps. • "Fusion" would represent the second step (also see [START_REF] Wessels | An ever c loser fusion? A dynamic macropolitical view on i ntegration processes[END_REF], for more on the fusion thesis). Fusion was understood to mean that national and EU structures would become organically connected. National processes of interaction would be increasingly influenced by the EU, with a "change of policy styles" as the potential outcome (Wessels, 1996: 36).

• "Convergence" was presented as the third step, where "we expect that the constitutional and institutional set-up of member states will converge towards one common model, which is not yet achieved but which is … 'in the making'" (Wessels, 1996: 36). Thus "the pre-existing differences among member states will slowly, and partly unnoticed, disappear".

The conclusion reached from the study of eleven member states was that there is evidence of Europeanization and of fusion but the findings on convergence were quite limited (see Rometsch and Wessels, 1996b; also see [START_REF] Schmidt | European integration and democracy: The differences among the member states[END_REF].

Most definitions of Europeanization (see Box 1) are not as specific as that offered by Wolfgang Wessels; rather they cover more than one of his stages of adaptation to the challenges of the EU. Nevertheless, many of the empirical studies of adaptation, especially of the Europeanization of government institutions, have addressed the spectrum of adaptation covered by his three steps (see below).

A slightly different enterprise from that of Dietrich Rometsch and Wolfgang Wessels was subsequently undertaken by Kenneth Hanf and Ben Soetendorp (1998a). Their distinctive contribution was to assemble a collection exploring the adaptation of small states to European integration. Hanf and Soetendorp expand on Robert Ladrech's formulation of Europeanization and focus on three particular areas of adaptation: governmental, political and strategic (1998b: 7-12). The first of these is largely self-explanatory. The second relates to adaptation on the part of key social groups and political parties. And the third embraces changes in negotiating strategy arising from the imperatives of the EU. Apart from the somewhat surprising inclusion of Spain as a small member, the collection also includes two non-members, Norway and Switzerland. The findings of this book are largely empirical.

Implementing European policies at the national level

Comparative studies on the national executives, parliaments and judiciaries are also important to understand the manner in which European policies are implemented at the national level (Siedentopf and Ziller, 1988;[START_REF] Rideau | Les Etats membres de l'Union européenne. Adaptations, mutations, résistances[END_REF]. As explained in the previous section, interest in the implementation of European policies has grown up after the Single European Act in fields like regional policy, economic policy or social policy. However, only recently has this literature become linked with that of Europeanization (e.g. [START_REF] Héritier | Differential Europe. The European Union Impact on National Policymaking[END_REF][START_REF] Knill | The Europeanisation of National Administrations Patterns of Institutional Change and Persistence[END_REF].

Much of the literature on the impact of EU policies argues for the convergence of national public policies. Again, there is a gap between the institutional studies on implementation which insist on the structural differences between the executives, the parliaments and the courts [START_REF] Rideau | Les Etats membres de l'Union européenne. Adaptations, mutations, résistances[END_REF] and the policy-oriented studies which insist on the process of convergence (Mény, Muller, Quermonne, 1995). Some institutional approaches of the implementation of European policies at the national level nevertheless identify more explicitly the "pendulum" between differentiation and convergence (Wallace and Wallace, 2000;[START_REF] Schmidt | Europeanization and the dynamics and mechanics of economic policy adjustment[END_REF]. Lequesne has discovered for instance that the implementation of the Common Fisheries Policy is very different in France, Spain and the United Kingdom because of the structural differences in the relations between national politicians, administrations and industries in each country. These differences have an impact on the acceptance of the Common Fisheries Policy by the social actors -in this case the fishermen -who sometimes have the feeling of unequal treatment from the EU [START_REF] Lequesne | L'Europe bleue. A quoi sert une politique communautaire de la pêche[END_REF].

Rediscovering government-interest group relations

Empirical studies on the relations between a specific government and interest groups in the EU context are not so numerous. Some studies have tried to investigate how publicprivate interactions in the national policy processes have been modified by EU membership.

As Goetz argued: "Much of the discussion which takes place under the banner of (new) governance, understood […] a more co-operative mode where state and non-state actors participate in mixed public/private networks" (Goetz, 2000:214). Taking into account one specific policy sector in one or several member-state(s), some scholars have studied how European integration has re-moulded national cooperative arrangements between the state and sectoral interest groups (Fouilleux, 2000). The relevant questions are then: does the EU undermine or not the basis of corporatist style arrangements in the national context? Does it introduce more pluralism in the relations between the government and the interest groups?

STOCKTAKING AND FUTURE RESEARCH ORIENTATIONS

EU-member state relationships remains an important issue for research. To make further progress in understanding, we need to go beyond the question of Europeanization of the national policy processes and of the adjustment of national institutions to the EU. But we have also to conclude from our analysis that new questions seem to be relevant fields of investigation for future research

• Having now a lot of studies on the impact of the EU on the domestic level (outside-in studies) research has to learn more about the impact of the member states on the EU level (inside-out studies). The policy-oriented literature which takes place under the banner of new governance was clearly an attempt to break from intergovernmentalism and to give more importance to non state actors involved in policy networks. In doing so, it has neglected the intergovermental dimension of the EU policy-making. More studies have to be undertaken on the role of national executives in the Council of Ministers, on the modus operandi of negotiation and coalition practices within the EU Council and, more generally, on the role of the member states inside the Commission directorate generals and cabinets [START_REF] Lequesne | The European Commission: A balancing act between autonomy and dependence[END_REF][START_REF] Donnelly | The college of the commissioners and their cabinets[END_REF], or inside the European Parliament [START_REF] Costa | Le Parlement européen : une assemblée délibérante[END_REF].

The perspective of future enlargements will increase the activities of member states at the EU level but also make them more diffuse. It is already interesting to analyse the domestic organisation of the candidate countries and the institutional channels they are using in negotiations with Brussels [START_REF] Goetz | European integration and national executives: A cause in search of an effect[END_REF].

• Revisiting as a matter of priority the role of national institutions at the EU level does not mean that we know enough about the Europeanization of societal actors at the domestic level. Further studies have to be produced on the changes or stability of interest groups, associations, political parties [START_REF] Mair | The limited impact of Europe on national party systems[END_REF], but also individuals. As Laura Cram wrote, very little evidence exists on "the preferences of members of social groups or movements involved in EU level institutions" [START_REF] Cram | The europeanisation of societal actors: Domestic institutions and the boundaries of the possible[END_REF]. We need to identify more clearly the mechanisms through which the EU influences the preferences of these individuals and also the impact which domestic institutional structures may have upon their adaptation. These questions plead for developing more micro-sociological approaches of societal actors in the member states, with a strong comparative basis.

• If a lot of studies exist on the Europeanization of national institutions and policies, little has been said about the impact of Europeanization on political representation. The propensity of national non-state actors to be involved in policy networks at the European level has probably changed the relationships with their political representatives (ministers, MPs) at the national level. Several questions come to light.

Has the development of interest representation at the EU level decreased the legitimacy of political representatives at the national level? Is a European substitute to national political representation emergent at the EU level through the European Parliament or is the EU level mostly restricted to interest representation? These questions should be addressed, shifting the study of the EU from the problem of the policy-making to the problem of supranational democracy [START_REF] Habermas | Après l'Etat-nation. Une nouvelle constellation politique[END_REF].

• Finally, the impact of the European Union on the political economy of the member states is a further area which deserves greater attention. It has not been neglected, to be sure. However, with the introduction of the euro, the Europeanization of the political economy of the euro-zone becomes an ever-more apposite issue. Is integration encouraging convergence on a single economic "model"; or are national characteristics resistant to this development?

Box 1: Definitions of Europeanization Ladrech (1994: 17): "Europeanization is an incremental process reorienting the direction and shape of politics to the degree that EC political and economic dynamics become part of the organizational logic of national politics and policy-making".

This definition was made in the context of empirical examination of constitutional change within France. Börzel (1999: 574): "a process by which domestic policy areas become increasingly subject to European policy-making".

This definition was made in connection with a study of sub-national policy responses within Spain and Germany. Risse, Cowles and Caporaso (2001: 3): " the emergence and development at the European level of distinct structures of governance, that is, of political, legal and social institutions associated with political problem solving that formalizes interactions among the actors, and of policy networks specializing in the creation of authoritative European rules" (italics in original).

This definition was made in connection with a project exploring change in domestic institutional and policy structures. Radaelli (2000: 2-3): Europeanization refers to: "Processes of (a) construction (b) diffusion and (c) institutionalisation of formal and informal rules, procedures, policy paradigms, styles, 'ways of doing things' and shared beliefs and norms which are first defined and consolidated in the making of EU decisions and then incorporated in the logic of domestic discourse, identities, political structures and public policies". This definition arises from an encompassing survey of t he majority of relevant literature on Europeanization. Bulmer, Burch et. al. (2001): "A set of processes through which the EU political, social and economic dynamics interact with the logic of domestic discourse, identities, political structures and public policies". Note: this definition builds on one used by Radaelli in an earlier draft of his 2000 paper.

This definition was developed for application to understanding institutional change within the institutions of UK governance.

  as a concept should be to ensure precision of use, whilst not pre-empting empirical findings. Box 1 highlights six different definitions. The first two -those by Ladrech and Börzel -are tailored rather to the specific empirical field of enquiry. The remaining three attempt a more encompassing definition. It is striking that the definition used by Risse, Cowles and Caporaso comes close to being synonymous with European integration. However, the concern of their project with domestic change brings their interest into line with other scholars of Europeanization.

In this section, several elements are taken from the chapter published by Christian Lequesne, "The European Union: how to deal with a strange animal", in Marie-Claude Smouts (ed), The new international relations(London, Hurst, 2001, 55 -87) .