Liesbet Hooghe

What Drives Euroskepticism? Party-Public Cueing, Ideology and Strategic Opportunity

On the surface, not much has changed in the European Union (EU). Its welloiled institutional machinery continues to produce directives, regulations, and decisions. Business goes on as usual. But the rejection of the European Constitutional Treaty in the heartland of Europe in the spring of 2005 was a watershed. The permissive consensus that shielded the machinery's operators from accountability is not just under strain; it is broken.

At stake here is not merely a particular outcome but the way in which decisions are made. 1 Since the 1990s, European integration has become measurably more contentious -in the media, in social movements, and, most prominently, among national political parties and public opinion (

of strategic interaction among party elites in their competition for political power [START_REF] Hooghe | A Postfunctional Theory of European Integration: From Permissive Consensus to Constraining Dissensus[END_REF].

Politicization, ideology, and strategy

This special issue puts two topics on the table. The first is concerned with the preferences of political parties as regards European integration. To what extent are parties driven by strategic incentives in the context of electoral competition; to what extent are they driven by durable ideological commitments? The second topic concerns the linkages between parties and public opinion: to what extent do voters and political parties cue each other? Whose preferences are driving European decisions -those of voters or those of political parties? Although these two sets of questions have been pursued independently in scholarly research, they are intimately connected -an answer to one question presupposes an answer to the other.

One compelling line of argument is a bottom-up view of preference formation in which voters' preferences provide a structure of incentives for party positioning in the context of electoral competition. This is the dominant view in analysis of party positioning, particularly from a rational choice perspective [START_REF] Downs | An Economic Theory of Democracy[END_REF]. The idea here is that at least a minority of voters have stable and transparent attitudes that affect their vote choice [START_REF] Zaller | The Nature and Origins of Mass Opinion[END_REF]. The bottom-up view can be extended to public opinion [START_REF] Stimson | Public Opinion in America: Moods, Cycles, and Swings[END_REF]. Political parties respond to the public mood on European integration, and this constrains decisions to a zone of acquiescence that cannot depart too far from the median voter [START_REF] Carrubba | The Electoral Connection in European Union Politics[END_REF].

A diametrically opposite, but equally plausible, line of argument is that political parties cue mass publics. From Seymour Martin [START_REF] Lipset | Cleavage Structures, Party Systems and Voter Alignments: An Introduction[END_REF] to Stefano [START_REF] Bartolini | Restructuring Europe: Centre Formation, System Building, and Political Structuring between the Nation State and the European Union[END_REF], it has been argued, and empirically shown, that the structure of party competition is both resilient and powerful in shaping party positioning. In this view, political parties are organizations with historically rooted orientations that guide their response to new issues [START_REF] Marks | The Past in the Present: A Cleavage Theory of Party Positions on European Integration[END_REF]. Elites, not masses, have coherent ideological maps with which they can make sense of highly technical and multifaceted issues, such as those arising from European integration [START_REF] Druckman | On the Limits of Framing Effects: Who Can Frame?[END_REF][START_REF] Jennings | Ideological Thinking among Mass Publics and Political Elites[END_REF]. Citizens can rarely grasp the complexities of an issue and look to public actors, particularly political parties, for cues [START_REF] Ray | Reconsidering the Link between Incumbent Support and Pro-EU Opinion[END_REF][START_REF] Steenbergen | Modeling Multilevel Data Structures[END_REF].

The implication of the latter view is that it usually takes epochal change to redraw the battle-lines. We know that the structure of domestic competition powerfully constrains attitudes towards European integration [START_REF] Aspinwall | Preferring Europe: Ideology and National Preferences on European Integration[END_REF]Marks and Steenbergen, 2004;[START_REF] Marks | Party Competition and European Integration in East and West: Different Structure, Same Causality[END_REF]. A party's orientation to European issues can be predicted fairly accurately if one knows where that party stands on an economic Left/Right dimension and a noneconomic or new politics dimension. But how these dimensions relate to a party's views on European integration may change -though slowly -in response to changes in the EU, and how these intersect with the domestic structure of conflict. Hence, as the European Union has mutated from a trade regime to a federal-type polity, partisan and public attitudes have shifted [START_REF] Eichenberg | Maastricht's Blues: The Transformation of Citizen Support for European Integration, 1973-2004[END_REF][START_REF] Marks | The Past in the Present: A Cleavage Theory of Party Positions on European Integration[END_REF]. In the early decades of European integration, Euroskepticism 2 was rooted in opposition to market integration [START_REF] Gabel | Interests and Integration: Market Liberalization, Public Opinion, and European Union[END_REF]. Since the Maastricht Treaty, it has taken on an additional dimension: defense of the national community [START_REF] Hooghe | A Postfunctional Theory of European Integration: From Permissive Consensus to Constraining Dissensus[END_REF]Kriesi, in this issue). Change in the character of European integration may also affect domestic contexts differently. Extensive European authority in market regulation looks more attractive to market liberals in social democratic regimes than to their ideological allies in market liberal regimes [START_REF] Brinegar | Varieties of Capitalism and Political Divides over European Integration[END_REF][START_REF] Marks | Conclusion: European Integration and Political Conflict[END_REF]. Likewise, strengthening supranationalism may be more compatible with some collective conceptions of national identity than with others (Diez [START_REF] Medrano | Framing Europe: Attitudes to European Integration in Germany, Spain, and the United Kingdom[END_REF]. Hence this view argues that economic interest and identity shape the views of political parties, but that the causal weight and the direction of these factors vary across time and space.

This conception of slow-paced, ideologically filtered change in party positioning is radically different from one that conceives of party preferences primarily as adjustment to electoral-strategic incentives. The latter view opens up the possibility that parties may shift positions on Europe as they go in and out of government, scent electoral gain, and use Europe as a lever to exploit dissent in their opponents, or as a strategy to alter the political agenda.

Each of these views is nuanced. The bottom-up view focuses on voters as a source of party positioning. Parties can receive an intelligible signal from voters even if a majority of voters do not comprehend an issue. As long as a minority of voters have structured views, parties may be able to pick up a signal from a noisy background. But the issue must be salient enough for a minority of voters. Top-down theory views parties as sources of information for voters. If parties send weak or mixed signals, either because they wish to avoid competing on an issue or because they are internally divided, this should reduce their cueing capacity.

Analyses of party/voter cueing and party positioning are interdependent. One purpose of this special issue is to bring these two topics together and to spur both contributors and readers to rethink their conclusions about the dynamics of politicization in the European Union.

Overview of the special issue

To what extent does cueing on European integration take place, and, if it does, in what direction? What is the role of ideology and of electoral-strategic incentives in party positioning on European integration? Prior research has produced contradictory answers to both questions. The contributions in this special issue advance a variety of methods to probe these questions.

Marco Steenbergen, Erica Edwards, and Catherine de Vries develop a model that investigates the relative strength of top-down and bottom-up cueing. Their conceptual point of departure is that these types of cueing are complementary, and that their relative strength depends on characteristics of the electoral and party system, party elites, and party supporters. Contrary to popular perceptions, the authors find scant evidence that political elites are out of touch with citizens or with EU policies. That said, there are clear differences among parties: extremist parties appear the strongest cuers and mainstream parties the weakest. The reason, the authors claim, is that mainstream parties attract relatively few opinion leaders and, when opinion leadership is weak, so are bottom-up as well as top-down linkages. Modeling conditional reciprocal causation poses problems of endogeneity and estimation. The authors tackle these by means of an instrumental variable approach embedded in dynamic simultaneous equations models to estimate bottom-up and top-down effects over a time-span of almost two decades (1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002).

Matthew Gabel and Kenneth Scheve examine party cueing among mainstream parties. Since mainstream parties collect the lion's share of the vote, their linkage with voters is decisive in how politicization affects European integration. They argue that these parties send out multiple cues rather than a single cue. A major source of this divergent party cueing is internal party dissent. Internal bickering creates incentives for party supporters to filter cuetaking: it frees party supporters from adhering to a single party line, and invites them to use their own beliefs to select among diverse party cues. The argument builds on John [START_REF] Zaller | The Nature and Origins of Mass Opinion[END_REF] insight that, where elite cues diverge, citizens accept cues consistent with their interests, values, and political predispositions. Parties are not unitary actors, yet being divided does not necessarily deprive them of influence. This argument provides a neat explanation for the apparent disconnect between pro-EU parties and Euroskeptic followers in, say, constitutional referendums.

The Constitutional Treaty referendums of 2005 constitute a perfect occasion for observing how parties negotiate ideological credibility and electoral-strategic opportunity. As Ben Crum shows, the dilemma is severe for mainstream opposition parties whose ideology leads them to support European integration, but whose opposition status induces them to fight the government. Crum finds that parties gave more weight to ideology than to strategic posturing, because pro-European mainstream opposition parties tended to side with government parties on the 'Yes' side. However, collusion with the government cost opposition parties dearly, in that it undermined their ability to cue party supporters. One reason for this is factionalism, an argument consistent with Gabel and Scheve. Factionalism alone, though, cannot explain the depth of the party-voter disconnect. Crum suggests that voters approach European integration primarily as a second-order issue, that is to say, as a strategic test ground for national government popularity. That makes it difficult for opposition parties to argue a 'Yes' vote for the Constitutional Treaty on ideological grounds, since it is a government project. Hence, where opposition parties do not play the standard opposition game, they may invite their supporters to turn to protest parties, which exploit the EU issue for their own strategic purposes.

Analyzing media reporting on national elections campaigns, Hanspeter Kriesi evaluates the strength of government/opposition dynamics versus ideology in influencing the salience and direction of party positioning on European integration in six West European countries -Austria, France, Germany, the Netherlands, Switzerland, and the UK. Kriesi finds considerably more support for ideology than for government/opposition dynamics. Euroskepticism, he argues, is part and parcel of a broader 'new cultural cleavage' that pits the losers from globalization against the winners. However, the extent to which parties blame this sense of loss on European integration varies across countries. The linkage is strongest in the UK and Switzerland, where Euroskepticism resonates with deep-seated national cultural anxieties, and where the European issue has consequently become central in restructuring the party system. It is too early to tell whether European integration will become the universal battleground for winners and losers of globalization.

Whereas the preceding authors are primarily interested in mainstream parties, Seth Jolly sets his sights on a peculiar subgroup of fringe parties, namely regionalist parties. Non-mainstream or fringe parties are often considered to be the kernel of Euroskepticism, and there are good ideological and electoral-strategic reasons for this. But regionalist parties do not appear to live by this law. As a group, they are consistently more pro-European than are other small party groups and nearly as pro-European as Christian democrats, socialists and liberals. This holds across time, space, and EU policy. Why is that so? Jolly demonstrates that regionalist parties favor European integration over and beyond ideological compatibility or electoral incentives because European integration makes smaller states more viable. A multi-level European Union is an unwitting ally against central governments.

The special issue ends with a reflective forum piece by Simon Hix, which sets out a rationalist institutionalist framework for understanding Euroskepticism. Echoing a basic assumption underlying most contributions here, Hix argues that Euroskepticism is best conceived as a rational response by citizens (and parties) for whom centralized EU power is a threat to their interests -not as deep-seated dissent from the political system. Support of and opposition to European integration are two sides of the same coin -both are contextual responses to changing interests. The upshot is that the Euroskeptics of today may become tomorrow's Euro-supporters if their fortunes were to improve in the EU's competitive multi-level polity. Although Hix probes the economic underpinnings of Euroskepticism, his framework provides a useful starting point for a dynamic comparative analysis of noneconomic as well as economic sources of EU positioning among citizens and parties.

Notes

1 In that sense, the neo-functionalists were right in arguing that European integration is self-transforming [START_REF] Haas | The Uniting of Europe[END_REF][START_REF] Schmitter | Three Neofunctional Hypotheses about International Integration[END_REF]. As European integration deepened, so the character of the process itself changed. 2 We have decided to leave the contributors to the special issue free to choose the spelling of the word 'Euros(k)(c)epticism'. Both versions are correct, though one tends to find the 'c' spelling on the European side of the Atlantic and the 'k' spelling on the American side.

European Union Politics 8(1)

About the author

Liesbet Hooghe holds the Chair in Multilevel Governance, Department of Political Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands, and is also Professor of Political Science at the University of North Carolina at Chapel Hill, USA.


Ben Crum

Party Stances in the Referendums on the EU Constitution Causes and Consequences of Competition and Collusion

Keywords:

This article examines political party behaviour around the referendums on the EU Constitutional Treaty in 2005. Starting from the presumption that this behaviour needs to be analysed in the light of the domestic government-opposition dynamics, a set of hypotheses on the causes and consequences of party behaviour in EU Treaty referendums is developed and reviewed for the EU member states in which a referendum was held or anticipated. As it turns out, with the exception of some right-conservative parties, all mainstream parties endorsed the Constitutional Treaty. However, because significant proportions of opposition party supporters are bound to go to the 'No' side, government parties are eventually crucial in securing a majority in favour of EU Treaty revisions.

The damning verdict of the electorates in France and the Netherlands over the proposed Constitutional Treaty for Europe revealed a deep divide between the people and their political representatives. Had the political elites of the two countries simply left the ratification to the national parliaments -as they did in the case of the previous EU Treaty revisions of Nice and Amsterdam (although France did have a referendum on the Treaty of Maastricht that narrowly passed) -the Constitutional Treaty would have passed by comfortable majorities. It is notable that, even in the referendums in Spain and Luxembourg which did come out in favour of ratification, electoral support for the Constitutional Treaty lagged significantly behind the level on which it could count among parliamentarians. Six more EU member states had been committed to a referendum on the Constitutional Treaty: the Czech Republic, Denmark, Ireland, Poland, Portugal and the United Kingdom. However, they decided to suspend their ratification processes because the results in France and the Netherlands led the European Council to call for a 'period of reflection'.

This article examines political party behaviour around the Constitutional Treaty referendums. I argue that this behaviour is determined by the interplay of party ideology with the position of the party within the party system. In particular, the article focuses on the basic asymmetries between government and opposition parties. First, as concerns the conditions under which parties determine their stance, opposition parties can exercise a genuine choice whereas government parties are basically constrained to commit themselves to the 'Yes' side. Depending on the decision made by the opposition parties, either one finds the divide between the 'Yes' and the 'No' camps coinciding with the divide between government and opposition (what I will call 'the Competitive Model') or one finds all the main parties campaigning together in favour of ratification ('the Collusive Model'). Secondly, however, when it comes to bringing their stance to bear upon the referendum, the choice enjoyed by opposition parties actually becomes a liability because they are prone to intra-party dissent and defection, especially when they choose to collude with the government. Moreover, because opposition parties cannot be counted on to deliver their constituency to the 'Yes' camp, the outcome of the referendum depends crucially on the ability of governing parties to mobilize their supporters.

Building upon previous research, the first sections develop a set of hypotheses on the causes and consequences of party behaviour. In the second part of the article these hypotheses are tested against actual events around the referendums on the Constitutional Treaty. With regard to the causes of the party behaviour, the analysis involves all 10 countries in which a referendum was planned because, in anticipation of the referendum, political parties had already committed themselves to one side or the other. The subsequent analysis of the consequences of party behaviour is inevitably limited to the four countries in which a referendum actually took place.

'Issue-voting' versus 'second-order' ballots

Central to the literature on national referendums on EU treaties is the divide between those who argue that it is domestic politics that determines the outcomes of these referendums and those who maintain that these outcomes do indeed reflect the well-considered views of the public on the issue at stake. The more sceptical argument that insists on the prevalence of domestic politics basically extends the concept of 'second-order elections' to EU referendums. [START_REF] Reif | Nine Second-Order National Elections: A Conceptual Framework for the Analysis of European Election Results[END_REF] introduced this concept to highlight the dominance of national political preoccupations in elections for other levels of government. Characteristically, voting behaviour in second-order elections tends to reflect an appreciation of national politics rather than of politics at the level at issue. Thus, extending the argument, one can hypothesize that referendums on European issues risk getting entangled in national political dynamics rather than reflecting a genuine consideration of the issue at hand. Following this line of argument, Franklin, Marsh and McLaren have suggested that 'referendum votes held to ratify [the Maastricht Treaty] are better interpreted as decisions made on short-term, national, rather than on long-term, European considerations' (Franklin et al., 1994: 470).

However, this sceptical line towards the issue relevance of European referendums has been contested. Most notably, empirical studies of referendums in Denmark and Ireland seem to revalidate the claim that sincere issue preferences do play an important role [START_REF] Svensson | Five Danish Referendums on the European Community and European Union: A Critical Assessment of the Franklin Thesis[END_REF][START_REF] Garry | Second-Order" versus "Issue-Voting" Effects in EU Referendums: Evidence from the Irish Nice Treaty Referendums[END_REF]. Not surprisingly these are the two EU member states that have a tradition of referendums and a longer-standing experience with referendums on European treaties. Indeed, confronted with these findings, Franklin has conceded that referendums may be decided by the merits of the case if voters have been able to develop in-depth knowledge and enduring preferences on the issue (see Ray, 2003a). Still he maintains that government standing is bound to be significant 'in other countries that hold referendums on European topics, since in other European Union countries opinion regarding Europe is less well developed' (Franklin, 2002: 756).

Regardless of which tendency preponderates, voters in European referendums face a choice that Schneider and Weitsman (1996: 583) have called the punishment trap:

Voters may have to choose between accepting an agreement on the basis of its merit and risk rewarding a government that has not successfully managed domestic politics, or rejecting the treaty, thereby punishing a popular government that negotiated and supported ratification of the agreement.

In turn, this dilemma is reflected in the choices that political parties face. When voters have only limited information, political parties can provide voters with important 'cues' about what is at stake in the referendum and how they should cast their vote (LeDuc, 2002: 722; see also [START_REF] Lupia | The Democratic Dilemma: Can Citizens Learn What They Need to Know[END_REF]. Voters who have come to associate their political opinions with certain political parties may well rely on these political parties to provide them with a pointer on how to position themselves in relation to a political choice about which they have insufficient knowledge.

The distinction between issue-oriented and second-order referendums not only operates at the level of the electorate but affects parties as well. If indeed voters approach referendums as second-order national elections, then parties may well want to recognize this in their strategies. Furthermore, this is a recursive relationship since the strategy that parties adopt may in turn influence voters' perception of the referendum. As Ray (2003b: 273) puts it: 'Not only do parties provide cues to voters, but individuals approach EU referendums and questions of further integration with an eye on the consequences for the relative power of domestic political actors.' If parties choose to approach the referendum as a test of the government's standing rather than strictly on the basis of the issue at hand, they can have a big hand in reaffirming its second-order character.

The causes of party stances: Ideology and strategy

The issue of determining a position on EU Treaty revisions is more obvious for some parties than for others. In seeking explanations of the stance parties take towards EU treaties, we find the contrast between issue-voting and second-order effects reflected in the contrast between ideological and strategic factors. Ideologically, national party systems in Europe have generally come to be organized along a left-right axis, with socialist worker parties towards the left end and conservative parties towards the right [START_REF] Lipset | Cleavage Structures, Party Systems, and Voter Alignments: An Introduction[END_REF]. Although the issue of European integration has very much appeared outside this dimension, empirical studies demonstrate a remarkable degree of coherence in the way parties of similar political persuasion have accommodated it [START_REF] Marks | National Political Parties and European Integration[END_REF][START_REF] Hooghe | Does Left/Right Structure Party Positions on European Integration?[END_REF]Kriesi, in this issue). From the start of the integration project, centre-right parties have tended to look approvingly on it, especially as long as the emphasis was on market integration through liberalization. Centre-left parties may have been more reluctant initially, but gradually they too have come to embrace European integration once it moved more and more into issues of reregulation in spheres such as regional and environmental policy (Hooghe et al., 2004: 129). Outright opposition to Europe is mostly restricted to the ideological fringes occupied by parties that generally adopt a protest-oriented or anti-system stance [START_REF] Taggart | A Touchstone of Dissent: Euroscepticism in Contemporary Western European Party Systems[END_REF]. [START_REF] Hooghe | Does Left/Right Structure Party Positions on European Integration?[END_REF] thus suggest that support for European integration along the left-right axis can be seen as an inverted U-curve with low support being concentrated at the extreme ends on both sides.

In fact, [START_REF] Hooghe | Does Left/Right Structure Party Positions on European Integration?[END_REF] have proposed an alternative ideological axis that displays a simple, linear relationship in support for EU integration: the 'GAL-TAN axis'. According to their findings, support for European integration tends to be high among parties that can be characterized as green/alternative/libertarian (GAL) and low among parties that qualify instead as traditional/authoritarian/nationalist (TAN). The two ideological axes -left-right and GAL-TAN -cannot be reduced to one another because each captures a different aspect of European integration, left-right focusing on the economic aspect and GAL-TAN on the political aspect. On the left, one finds both GAL parties, such as the Greens, as well as parties with more of a TAN character, such as (former) communist and regionalist parties. Similarly, at the right end of the spectrum there are GAL parties of an outspoken liberal or libertarian character as well as nationalist parties with a TAN inclination.

Table 1 lists the position of all the main ideological families on economic and political integration and also presents an overall appraisal. There is clearly a distinct 'pro-integration core' (in bold type in Table 1) of social democrats, liberals and Christian democrats, who are ideologically inclined to endorse further integration both economically and politically. Euroscepticism is mostly to be found outside the ideological core. At the same time, one can observe Marks et al. (2002: 587). that, whereas for economic integration the centre of gravity of support tends to lie to the right of the centre, for political integration it tends to the left.

However, parties' ideological inclinations need not necessarily coincide with the strategic incentives created by the context of EU Treaty referendums. First and foremost, government parties are bound to endorse Treaty revisions because these revisions are established only with the approval of each and every government involved. The ratification that follows basically involves the government getting the result of the international negotiations approved at home. Thus government parties will be expected to endorse the negotiation result; moreover, a failure to ratify will cause a loss of face vis-à-vis the other governments. Because parties in government are mostly affiliated to the ideological pro-integration core, few of them experience a tension between their positional incentives and their ideological inclination. This is less self-evident when we turn to opposition parties, which may be tempted to use EU referendums as a means to mobilize against the government in power. Indeed, this is exactly what we find among protest parties that are resigned to remaining in opposition indefinitely. However, opposition parties that expect to return to office face a more complex calculation (see [START_REF] Franklin | Uncorking the Bottle: Popular Opposition to European Unification in the Wake of Maastricht[END_REF]Hug and Sciarini, 2000: 7). Tempting as it may be for them to use the referendum as a means to mobilize against the government, such a move might alienate them from future coalition partners. Moreover, when a Treaty change does come to be adopted, a party will find itself obliged to abide by its terms once it does come into office, regardless of how it campaigned. Thus, given that EU Treaty changes are generally established by a broad European political consensus and that any party entering government will have little choice but to play by the rules, mainstream parties vying for office experience pressure to behave 'responsibly' and to campaign on the 'Yes' side. The adoption of such a responsible stance is all the more likely when a party is ideologically committed to a pro-EU position.

Whereas government parties are bound to endorse the EU Constitutional Treaty and protest parties are naturally inclined to oppose it, the main variation is to be found in the positioning of (mainstream) opposition parties. It follows that there are basically two different patterns of party positioning on EU Treaty referendums. On the one hand, there are party systems in which the government factions are left alone to defend the EU Treaty and all the opposition parties campaign against it. These systems I label 'Competitive Party Systems'. In contrast, 'Collusive Party Systems' are those in which the major opposition parties join the government on the side of the EU Treaty.

The distinction between the Competitive and the Collusive models highlights the crucial role of opposition parties in determining the configuration of party positions. Because the analysis of the strategic considerations these parties face remains inconclusive, ideological orientations are expected to prevail in determining the stance of mainstream opposition parties. A first hypothesis is then:

H1: When parties associated with the pro-integration ideological core (social democrats, Christian democrats and liberals) dominate the opposition, the distribution of party positions will resemble the Collusive Party Model.

Put the other way around, if the opposition is of a different ideological persuasion, we would expect to find the Competitive Model.

Competitive Party Systems would seem particularly conducive to introducing second-order considerations into the campaign, because every vote in favour of the EU Treaty may be regarded as a vote in support of the government position. In contrast, one would expect issue-voting to have more of a chance in collusive settings, because the way one casts one's vote does not involve a choice between government or opposition. Hence, I now turn to the consequences of party positions.

The consequences of party stances

Ultimately, we are interested in the stances of parties in EU Treaty referendums because of their presumed impact on voting behaviour in the referendum. 1 This impact can vary in terms of its direction -for or against the EU Treaty -and also its size; under certain conditions we may expect parties to have more leverage on the electoral decisions than under others. The consequences of the party stances adopted are bound to vary under the two models and for each of the three kinds of party. Previous research suggests that the ability of a party to sway its electorate is mediated by the general level of salience, intra-party unity and the visibility of inter-party disagreement [START_REF] Leduc | Opinion Change and Voting Behaviour[END_REF]Ray, 2003a; see also Steenbergen et al., in this issue).

One factor in which parties vary is their potential for maintaining internal unity and preventing internal factionalization. Ray (2003a) that a party's influence over its voters increases if it can maintain internal unity. Maintaining internal unity seems least of a challenge for protest parties, for which all the incentives point against EU Treaties (see Gabel and Scheve, in this issue). In the case of government parties, internal dissent is likely to be restrained owing to the responsibility incumbent upon them, although it may still be a factor in parties that are not ideologically predisposed to support European integration. Factionalization would appear most likely among parties that are exposed to contradictory incentives. 2 The preceding analysis suggests this is most likely among opposition parties. Even if these parties and their leaderships are formally committed one way or the other, they are likely to face contrary sentiments within their party, thus leading to factionalism (see Taggart, 1998: 369). This applies in particular to opposition parties of a pro-European persuasion: if they follow their ideology, followers will accuse them of 'sleeping with the enemy', whereas if they choose to campaign in the 'No' camp, they will be accused of letting strategy prevail over substance (see Franklin et al., 1994: 466).

H2: Opposition parties that decide to collude with the government are liable to factionalism.

More generally, Ray has found an inter-party disagreement effect in that 'the effect of party positions is significantly greater when parties take a variety of positions on the issue of European integration' (Ray, 2003a: 988; but see also Steenbergen et al., in this issue). In other words, ceteris paribus, parties under the Competitive Model will be more successful in swaying their voters than those under the Collusive Model since, owing to the reinforcement of the second-order character of the EU Treaty referendum, mainstream parties will have a stronger claim on the loyalty of their followers. Under the Collusive Model, in contrast, the ability of the mainstream parties, both in government and in opposition, to command their voters will tend to decrease, whereas protest parties are likely to benefit from their relative isolation and are able to increase their grip on their voters. Even if the signal from the governing parties remains unequivocal, the pressure on their electorates loyally to follow the party line will decrease.

Again the spotlight is on the role of the main opposition parties. The dilemma these parties face between ideological and strategic inclinations can be expected to spill over to their electorates (see [START_REF] Schneider | The Punishment Trap: Integration Referendums as Popularity Contests[END_REF]. Because opposition parties reflect different inclinations, the readiness of their voters to follow their lead is likely to be reduced; alternatively, following the suggestion by Gabel and Scheve (in this issue), intra-party disagreement offers the party constituency a choice in being 'influenced by those elites in the party who share their interests, values, and predispositions'. In any case, H3: Opposition parties will be less successful than government parties in swaying their supporters to their side.

In fact, Franklin et al. (1994: 463; but see [START_REF] Hug | Referendums on European Integration: Do Institutions Matter in the Voter's Decision?[END_REF] have found this hypothesis confirmed in the case of the three referendums on the Maastricht Treaty: 'Those [pro-Treaty parties] in government did well enough but those in opposition, whatever their European credentials, saw their supporters significantly divided between "yes" and "no" camps.'

In particular, it is suggested that, whichever way the main opposition parties go, the government has little reason to stake its desired positive outcome of the referendum on the followers of these parties. Because the Competitive Model pits the government against the opposition as a whole, the key to the referendum outcome is in the hands of the government parties. The referendum is in many respects bound to turn into a test of the standing of the government. LeDuc (2002: 728) has called this situation an uphill struggle:

The [government] party initiating the referendum knows that it can count on the votes of its core supporters. It knows also where the additional votes may lie that it needs in order to secure a majority and that it can win these only through a hard fought campaign.

The government can win the referendum if it is able to re-establish the majority by which it was elected. Although this capacity is likely to vary from moment to moment and from government to government, electoral cycle theories would suggest that governments that are still in the early days of their victory have the best hope of swinging the referendum to their side.

Given that protest parties will mobilize against EU Treaty revisions and that electoral support from opposition supporters is insecure (at best), we find that under the Collusive Model too it falls upon government parties to lay the basis for a positive outcome by securing the loyalty of their own followers. In particular, the opposition's joining the 'Yes' side is a handicap to the extent that it reduces the pressure on government parties' followers by downplaying the second-order character of the referendum. Compared with the 'uphill struggle' scenario of the Competitive Model, in the Collusive Model one would expect the 'Yes' side to gain some support from loyal followers of the main opposition parties, although this might come at the cost of loosening the grip of the government parties on their electorate. The question then becomes which of these two effects outweighs the other.

Party stances in the EU Constitution referendums

By spring 2005 almost all political parties in the 10 countries in which a referendum on the European Constitutional Treaty was planned had determined their stance on the issue (see Table 2). 3 As expected, all government parties came out in favour of ratification of the European Constitutional Treaty. Only the Czech Freedom Union, which served as a junior partner in the governing coalition, had not fully committed itself in favour of the Constitutional Treaty.

For most governing parties, endorsement of the Constitutional Treaty was fairly unproblematic because they had consistently supported European integration over the years. Moreover, with the sole exception of the Portuguese Socialist Party, which came into office only after the negotiations had been concluded but whose support for the Treaty was in any case not in doubt, all these parties had been involved in the negotiations over the Constitutional Treaty.

As far as non-government parties are concerned the picture is more diverse. Three countries (the UK, Poland and the Czech Republic) conformed to the Competitive Model, whereas the other seven reflected the Collusive Model. It is notable that, in all three cases following the Competitive Model, the opposition was dominated by right-conservative parties. Typically, the British Conservatives and the Czech Civic Democratic Party (ODS) make up the European Democrats (ED) group within the European Parliament's Christian democrat-Conservative European People's Party-European Democrats (EPP-ED) group. The Polish case was rather unusual because the main opposition party at the time, the Christian democrat Citizens Platform, was reluctant to make up its mind on the Constitution and was experiencing severe pressure from other right-wing opposition parties that had adopted a strong anti-Constitution position. In contrast, centre-right parties in Spain, Portugal and Ireland stuck to their traditional pro-European orientation. In the case of Portugal and Spain this orientation was reinforced by the fact that the centre-right parties had only recently left office and had been representing their countries in (most of) the negotiations on the Constitutional Treaty. In the case of the Irish centre-right (Fine Gael), one needs to point out that it was opposing a right-wing government rather than a left-wing one, as was the case for the other Christian democratic opposition parties.

Whereas opposition parties that operate to the right of the centre may thus be tempted to come out against the EU Constitutional Treaty, such tendencies are completely absent from social democratic parties. Nor do we find opposition to the Constitutional Treaty among parties associated with the European Liberal Democrat and Reform (ELDR) group. Thus all centre-right governments know that the mainstream opposition parties are on their side.

Beyond the pro-integration ideological core, the only parties that supported the EU Constitutional Treaty as opposition parties were Green parties. Indeed, the majority of Green parties in the referendum countries (Denmark, France, Luxembourg, the Netherlands) came to endorse the Constitutional Treaty, even if this had not come about easily. Both the French and Danish Greens made their stance the object of an internal party referendum. In both cases the majority of the party membership (53% among the French Greens and 64% among the Danish Greens) came out in favour of the Constitutional Treaty. Indeed, if the ratification process had been continued, the Irish Greens, which had been a leading force in the anti-Nice campaign, would also have held a party referendum on the Constitutional Treaty. In Spain, the regionalist parties that are associated with the Green group in the European Parliament remained divided, with the Basque group choosing to endorse the Constitution and the Catalans opposing it.

Apart from the right-conservative parties that chose to campaign against a social democrat government and the Green parties that refused to join the pro-integration camp, opposition to the EU Constitutional Treaty was concentrated among the nationalist and extreme right, the extreme left and smaller protest parties. Without exception, all the parties associated with the European United Left (EUL) in the European Parliament opposed the Constitutional Treaty. The same would apply to all the parties associated with the right-wing Union for Europe of the Nations (UEN) were it not for the Irish Fianna Fail, which sits in government. The remainder of the opposing parties comprise anti-establishment and protest parties such as the French National Front, the Pim Fortuyn List in the Netherlands, the Action Committee for Democracy and Pensions Justice in Luxembourg, the League of Polish Families, and Self Defence of the Polish Republic.

The consequences of party stances Factionalization

The most notable case of party factionalization over the EU Constitutional Treaty was the French Socialist Party (PS). Although admittedly also provoked by motives of inter-and intra-party political strategizing, the internal divisions came to be articulated as ideological ones, with the opponents of ratification invoking the prospect of an 'Alter-Europe' (Ricard-Nihoul and [START_REF] Larhant | Constitutional Referendum in France[END_REF]; see also Eurobarometer, 2005b). Eventually, the party line was determined by way of an internal referendum in which 59% of the members who voted were in favour of the Constitutional Treaty. Still, this did not keep some prominent socialists from campaigning for a 'non'.

However, other social democratic parties in opposition, such as those in the Netherlands, Denmark, Luxembourg and Ireland, showed no significant signs of internal factionalization. For internal tensions similar to those in the PS we have to turn instead to right-wing opposition parties. One may for instance consider the ambivalent tendencies that the Czech ODS opposition harboured beyond the Eurosceptic rhetoric of its founder, Czech president Vaclav Klaus. A similar tension between the reflexes of opposition and the inclination to strike a responsible pose may account for the indecisiveness of the Citizens Platform and the Peasant Party in Poland.

Another group of parties liable to internal factionalization were the Green parties. Although many of the Green parties had opposed earlier EU Treaties, the majority of them tended to come out in favour of the Constitutional Treaty. This development may partly be attributed to a shift in the integration process towards (re-)regulation (see [START_REF] Hooghe | Does Left/Right Structure Party Positions on European Integration?[END_REF], but it may also signal a trend in which Green parties are increasingly shedding their anti-establishment views and merging into the political mainstream. Typically, in the case of the French and the Danish Greens, referendums were used to legitimize the change in party stance, and the Irish Greens refrained from adopting a position on the Constitutional Treaty.

One thing worth noting is what we may call the 'force of government': government parties remain distinctively immune from any significant factionalization (see Franklin et al., 1994: 466). Being part of the government and having been associated with the negotiations over the Constitutional Treaty, there have been few challenges to the official party line, even though in most government parties Eurosceptic voices have not been completely silenced. A good case in point is the Dutch People's Party for Freedom and Democracy (VVD), which in the run-up to the referendum maintained a united front, although in retrospect regrets have been expressed about the pro-Constitutional Treaty stance adopted [START_REF] Soetenhorst | Kamerlid Van Baalen betreurt keuze voor het ja-kamp bij referendum[END_REF].

Electoral sway

Of the four countries that held a referendum on the Constitutional Treaty in 2005, two (Spain and Luxembourg) produced a positive outcome and two (France and the Netherlands) a negative one. In all four cases, the electorates turned out to be considerably more sceptical about the Constitutional Treaty than their parliamentary representatives were (see Table 3). Even in the Spanish referendum, which occurred first and resulted in a comfortable majority of 77% for the 'Yes' camp, popular support still fell considerably short of the landslide endorsement that the Constitutional Treaty would have received in parliament. The negative referendum outcomes in France and the Netherlands revealed major gaps between the preferences of the parliamentary representatives and those of the people. In Luxembourg too the 57% popular support still fell far short of the prevailing inclination among the parliamentary representatives.

It is notable that these four cases all followed the Collusive Model, with the main opposition parties campaigning in favour of the Constitutional Treaty. The French, Dutch and Luxembourg cases are even more similar because here the main opposition party was the social democratic party, which together with the Green party campaigned side by side with a centre-right government. The 'No' campaign in these countries was thus left to anti-establishment parties on the (left and right) extremes of the political spectrum. The Spanish case is slightly distinctive because here the referendum was sought by the young social democratic government that only a year earlier had succeeded the centre-right People's Party (PP), which had led most of the Spanish negotiations over the Constitutional Treaty.

Zooming in on relations between the different parties and their sympathizers among the electorate, some interesting patterns emerge (Table 4). In all four countries we find that it is indeed the protest parties, combining their ideological opposition to Europe with practical opposition to the government, that have been most successful in cueing their followers to vote 'No'. Among the followers of these anti-establishment parties we generally see around 80% to 90% sharing the party position. The pattern is less convincing among the governing parties. Although most of them have a majority of their electorate on their side, many of them see their followers seriously divided, with as much as 25-50% defecting to the 'No' camp. However, as anticipated, the situation is most dramatic for pro-Constitution opposition parties, most of which in fact see the majority of their followers joining the 'No' camp. Basically, it was the loyalty of the supporters of the government parties that sealed the positive outcome of the referendums in Spain and Luxembourg. In the Spanish case, with a defection rate of no more than 7%, the followers of the social democrat Socialist Workers' Party (PSOE) alone almost sufficed to decide the issue. Also, because the majority of the PP electorate followed the official party stance, the 'Yes' vote increased to 77%. The positive result in Luxembourg was primarily secured by the effectiveness of Prime Minister Juncker's senior government party, the Christian Social People's Party (CSV), in keeping its followers in line. However, the other pro-Constitution parties in Luxembourg had much more mixed results, with the junior government partner (the Democratic Party, DP) seeing a considerable minority yielding to the 'No' camp and the electorates of the main opposition parties (the Luxembourg Socialist Workers' Party, LSAP, and the Greens) being almost evenly split between the 'Yes' and the 'No' camps.

In the French case, in contrast, it is the abysmal performance of the pro-Constitution opposition that is most striking. Having decided to endorse the 'Yes' camp after internal party referendums, the social democrat Socialist Party (PS) and the Greens (Verts) failed to sway their voters and found the majority of them defecting to the other side. However, although many commentators have located the chief cause of the French 'Non' in the divisions within the PS, one may wonder whether it is realistic to expect the opposition to shoulder the responsibility for a positive referendum outcome. Indeed, had the government parties been able to sway their own followers to the same extent as their Spanish or even their Luxembourg counterparts, the majority would have been within reach regardless of the performance of the opposition parties.

The Dutch referendum reinforces the argument that EU referendums eventually have to be won by government parties. In this case the poor performance of the government parties stands out, with their followers being almost evenly divided. The main opposition party, the Labour Party (PvdA) saw almost two-thirds of its followers defect to the 'No' camp so, given the effectiveness of the anti-Constitution campaign of the protest parties, the referendum was bound to go to the 'No' side.

Conclusion

On the basis of party data from the 10 countries that were committed to a referendum on the EU Constitutional Treaty and the results in the four countries where a referendum actually took place in 2005, this article has examined the factors that drive political parties to choose sides in referendum campaigns and the extent to which these choices condition the impact they can have on the eventual outcome. Theoretical considerations led me to focus in particular on the position taken by opposition parties, because they are likely to be torn between ideological inclinations and strategic considerations. Furthermore, whichever way the opposition decides to go determines very much the voters' perception of the options on offer. If the opposition sides with the government -what I have called the Collusive Model -the mobilization of the 'No' side is left to protest parties. If, however, the opposition chooses to oppose the government -the Competitive Model -the central divide in the referendum campaign coincides with that between the main parties.

A first finding is that, whereas one might expect certain tensions between ideological and strategic inclinations, in practice ideology predominates when parties determine their stance in the referendums on the EU Constitution. Parties that are defined as being part of the pro-integration ideological core (social democrats, liberals and Christian democrats) support the EU Constitutional Treaty regardless of whether they are in or out of government. This hypothesis has been confirmed as we found the Collusive Model obtaining in 7 of the 10 countries that were set to have a referendum and where the opposition is dominated by social democrats and/or Christian democrats and liberals. It is notable that, in the three cases where the Competitive Model occurs, the opposition is dominated by parties at the conservative end of the centre-right.

Interestingly, these findings suggest that the centre of gravity for support of the Constitutional Treaty has to be located to the left of the political centre. Another way to interpret this finding is that the Constitutional Treaty is less associated with economic integration than with political integration (see [START_REF] Marks | National Political Parties and European Integration[END_REF]. One implication of this is that, when the opposition is dominated by social democrats, the articulation of Euroscepticism will be left in the hands of anti-establishment parties. The experiences with the Constitutional Treaty referendums suggest that the issue of further European integration is likely to divide the political mainstream only when the opposition is dominated by right-conservatives.

The second hypothesis concerned factionalism and suggested that this is particularly likely among opposition parties that side with the 'Yes' camp. The French Socialist Party might figure as a very strong case in support of this thesis. However, although factionalization was indeed found only among opposition parties, joining the 'Yes' camp as a social democratic party was neither a sufficient nor a necessary condition for it. Among the other social democratic opposition parties endorsing a 'Yes' vote (in Denmark, Luxembourg, the Netherlands and Ireland) we find few signs of factionalization. On the other hand, the competitive strategy of the centre-right opposition in Poland and the Czech Republic did cause factionalism strains. Furthermore, inter-party became particularly visible among Green parties that switched from opposition to previous European treaties to support for the Constitutional Treaty.

Although opposition parties exposed to contradictory pressures may thus be able to prevent factionalism, the contradictions are much harder to suppress when it comes to the party electorate. Centre-left opposition parties are particularly vulnerable in this regard, because their ideological inclination is to join the 'Yes' camp whereas their followers tend to oppose a 'Yes' that is championed by a (centre-)right government. These problems of the major opposition parties stand in stark contrast to the success of protest parties in swaying their followers to vote 'No' on both ideological and strategic grounds.

Indeed, the four referendums held in 2005 confirm the expectation that positive outcomes cannot be staked on opposition voters. Because protest voters and some of the opposition's followers are bound to turn against the EU Treaty revisions, it is up to the government parties to win the referendum. This is where the Spanish and the Luxembourg government parties succeeded. In the Netherlands, in contrast, the pulling power of government parties turned out to be negligible. The French government parties performed better, but they fell far short of mobilizing the majority on which they had come to power.

It is tempting to reflect upon the counterfactual scenario if the opposition parties in France and the Netherlands had adopted a competitive strategy. For one thing, such a strategy certainly would not have prevented factionalism, as is indicated by the deep divisions that the internal party referendums revealed in France. It probably would have meant that an even larger share of the opposition vote would have gone to the 'No' camp. The key question, however, is whether, with the referendum adopting more of a 'second-order' character, the centre-right government parties would have been able to tighten their grip on their own followers. Thus one may doubt whether opposition parties did the government a service by joining its side. Unfortunately, we lack empirical evidence for contrasting cases in which the main opposition party did adopt a competitive stance.

Obviously, other factors too may influence the degree to which parties can hold sway over voters' choices in referendums. In particular, one may want to examine how party-voter relations are affected as EU referendums become more frequent. There are strong indications that party influence decreases when the knowledge and saliency of EU issues increase (Ray, 2003a). At the same time, Steenbergen et al. (in this issue) suggest that referendums are conducive to party-voter congruence, not so much because they increase the impact of parties on voters but rather because they 'force party elites to pay closer attention to their supporters'. To test these theses it would have been particularly interesting to analyse the referendums in Denmark and Ireland, where parties and voters have much more experience with EU referendums than do the countries analysed here (see [START_REF] Svensson | Five Danish Referendums on the European Community and European Union: A Critical Assessment of the Franklin Thesis[END_REF][START_REF] Garry | Second-Order" versus "Issue-Voting" Effects in EU Referendums: Evidence from the Irish Nice Treaty Referendums[END_REF]. Such analyses would become of particular value if the tendency to employ referendums in the ratification process persists and if indeed there are further Treaty revisions in the future. 1 One may also want to consider the reverse effect of (anticipated) voting preferences on party positioning. Indeed, the two effects do not necessarily exclude each other (Steenbergen et al., in this issue). However, given the focus on party stances in this paper and the fact that chronologically these are disclosed prior to the casting of the votes, here only the impact of party stances on voting behaviour is considered. 2 Kriesi (in this issue) reviews the possible determinants of party factionalization in the context of recent national election campaigns in six West European countries, confirming the importance of tensions between party role and EU stance for party factionalization. However, his findings suggest that this tension is 'more dangerous for Eurosceptics joining the government than for pro-European oppositions colluding with the government'.

Notes

Although I have no reason to challenge these findings as such, two qualifications are in order. First, national election campaigns, in which the EU issue generally plays a rather secondary role, constitute a rather different context from EU referendum campaigns. Secondly, in contrast to the anti-European parties in government -of which there have been very few so far (particularly in Western Europe) and about which I would hesitate to generalizepro-integration opposition parties are a much more general phenomenon with great actual relevance, as is also shown by the analysis below. 3 The analysis is limited to those parties that secured at least 4% of the popular vote in the most recent elections for the national parliament (as at June 2005). This implies that all government parties are included and also the main opposition parties, but only the most prominent of the protest parties are included. An additional consequence is that parties only (or mostly) active in elections to the European Parliament (Denmark) have been excluded. In total we are looking at 20 government parties and 37 opposition parties in the 10 countries, representing more than 90% of the total number of votes cast in the most recent elections for the national parliaments.

  2005, between UK elections of 5/5/2005 and Polish elections of 25/9/2005. Based on the EPIN Ratification Monitor (Kurpas et al., 2005). Vote shares based on www.electionworld.org. Y [plain text] -party in favour of Constitutional Treaty; N [bold italics] -party against Constitutional Treaty; U [italics] -party undecided on the issue. PES = Party of European Socialists; EPP-ED = European People's Party-European Democrats; ELDR = European Liberal Democrat and Reform group; UEN = Union for Europe of the Nations Group;EUL/NGL = Confederal Group of the European United Left -Nordic Green Left; EG/EFA = Group of the Greens / European Free Alliance; ID = Independence/Democracy Group; NA = non-attached.

  Earlier versions of this article were presented at the Workshop on 'Debating the European Constitution', chaired by Renaud Dehousse, at the 2005 epsNet Plenary conference, 17-18 June 2005 in Paris and at the Conference on 'Euroskepticism -Causes and Consequences' organized by Liesbet Hooghe and Gary Marks, 1-2 July 2005 in Amsterdam. I am grateful for the stimulating comments received at both these occasions.

Table 1

 1 Ideological predispositions of main European party families towards EU integration

	Ideological	Economic	Political	Overall stance on
	family	integration	integration	EU integration
	Extreme left/	Strongly opposed	Moderately	Strongly opposed
	communist		opposed
	Green	Moderately	Mixed	Moderately opposed
		opposed
	Social

democratic Moderately in Strongly in favour Moderately to favour strongly in favour Liberal Strongly in favour Strongly in favour Strongly in favour Christian Strongly in favour Strongly in favour Strongly in favour democratic

	Conservative	Strongly in favour	Strongly opposed	Moderately in favour
	Extreme right	Moderately	Strongly opposed	Strongly opposed
		opposed
	Note: Based on

  has demonstrated

	A. COMPETITIVE MODEL		B. COLLUSIVE MODEL
	YES	NO
	Government	Opposition	YES	Government	Opposition
		Protest parties	NO		Protest parties
	Figure 1 Two models of party behaviour in referendums.

Table 2

 2 Party positions in the 10 referendum countries

Table 3

 3 Shares of Constitutional Treaty supporters among parliamentary factions and electorateThe source of the vote shares is www.electionworld.org.

			B. Yes-parties	C. Yes-parties
		A. % Yes	seat share	vote share last
		electorate	Lower House	Lower House
		(% No)	(∆AB)	elections (∆AC)
	Spain	77% (23%)	95% (18)	86% (9)
	France	45% (55%)	93% (48)	70% (25)
	The Netherlands	38% (62%)	85% (47)	83% (45)
	Luxembourg	57% (44%)	92% (36)	87% (31)
	Note:

Table 4

 4 Distribution of voters in EU constitutional referendums by party proximity (%)

				Pro-			Anti-
	Government			Constitution			Constitution
	parties	Yes No	opposition	Yes No	opposition Yes No
	Spain (N = 1392)
	PSOE	93	4	PP	72	19	IU	32	61
				CDC/CiU	62	19	ERC	5	87
				PNV	42	57
	France (N = 1745)
	UMP/UDF	70	24	PS	35	55	FN/MNR	4	81
				Verts	33	50	PCF	6	90
	The Netherlands (N = 1640)
	CDA	53	47	PvdA	37	63	SP	13	87
	VVD	49	51	GL	54	46
	D66	51	49
	Luxembourg (N = 961)
	CSV	79	21	LSAP	49	49	ADR	23	77
	DP	55	42	Déi Gréng	48	49
	Notes: Blank answers disregarded, hence not all pairs sum up to 100%. Respondents' party
	proximity is determined on the basis of the following question: 'Which of the following parties do
	you feel the closest to or the least far from?'
	Source: Eurobarometer (2005a-d).

European Union Politics 8(1)

About the author

Ben Crum is a lecturer in political science, Department of Political Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands. Fax: + 31 20 598 6820 E-mail: BJJ.Crum@fsw.vu.nl