In multi-level systems, the erosion of democracy in one unit risks affecting the quality of democracy in other units and across the levels of the system. The European Union (EU), where democracy and the rule of law constitute fundamental community norms, faces this problem as several member states undergo democratic backsliding. While previous literature has investigated why the EU has so far been unable to prevent backsliding, its consequences for European integration remain unclear. This article investigates whether democratic backsliding in one member state reduces EU policy and regime support among citizens in other member states. Building on insights from behavioural economics, we argue that European citizens value reciprocal norm compliance and are willing to sanction norm-violating member states to ensure compliance with the rules of the game. Drawing on an original survey conducted in Germany, Italy, Poland, and Sweden, we find that citizens strongly support EU measures to fight democratic backsliding and support excluding norm-violating states from redistributive policies. However, information experiments do not provide evidence that democratic backsliding undermines EU policy and regime support. Nevertheless, our findings underline that citizens perceive democratic backsliding to be problematic and provide support for taking measures to counter community norm violations.

Democracy and the rule of law are fundamental community norms of the European Union (EU). However, so far, the EU has been unable to prevent several of its Member States from democratic backsliding. In this chapter, we investigate whether and, if so, how such norm violations affect public support for solidarity and co-operation in the EU. Building on insights from behavioural economics, we argue that European citizens value reciprocal norm compliance and are willing to sanction norm-violating Member States in order to sustain the norms of the political community and ensure compliance with the "rules of the game". Synthesising survey and survey experimental evidence from two recent research projects, we show that a majority of citizens are willing to exclude norm-violating states from participating in common EU policies and from reaping membership benefits. Our chapter concludes by cautioning that, in the long run, democratic backsliding might undermine support for the European integration project, more generally.

This article analyses whether and how fairness considerations affect citizens' support of European Union (EU) policies and integration. While past literature has revealed that perceptions of procedural and substantive fairness impact on public opinion at the level of the nation state, we know less about the fairness-support nexus when it comes to international cooperation. We here make use of the case of differentiated integration (DI) to experimentally dissect normative and utility-oriented considerations in the evaluation of EU policies. DI as an instrument to overcome heterogeneity-induced gridlock has been linked to both autonomy and dominance, and it can generate winners and losers in the EU. Our experiments reveal that citizens largely support DI. However, they are opposed to forms of DI which impose negative externalities on a subgroup of EU member states. This holds irrespective of the affectedness of citizens' own member states. We take these findings as a first experimental confirmation that citizens, indeed, care about the fairness of the EU and its policies.

In 2020, the German government supported the COVID-19 recovery fund 'Next Generation EU', which according to many observers is breaking with the taboo of joint EU debt liability. In this article, we analyse whether this decision marks a programmatic shift towards fiscal integration, taken in isolation by the Chancellor, or whether it can be reconciled with higher-level principles that guided the Chancellor's previous European policies? Our analysis builds on a synthetic framework combining a multi-level principal-agent account with ideational components. The empirical analysis of Bundestag debates and original public opinion data reveal that the support for 'Next Generation EU' neither breaks with the Chancellor's established 'conservational-pragmatic' approach to EU policy-making, nor separates the Chancellor from the preferences of the Bundestag and the public. Content analyses show how the government and its supporting camp in the Bundestag justified the apparent policy shift, underlining a strong agreement towards strengthening the EU in times of an unseen crisis, while at the same time revealing some noteworthy partisan differences.

Differentiated integration is often considered a solution to gridlock in the European Union. However, questions remain concerning its perceived legitimacy among the public. While research shows that most citizens are not, in principle, opposed to differentiated integration – although support varies across different differentiated integration models and different country contexts – we still know little about the role institutional design plays in citizens’ evaluations of differentiated integration. This article inspects how citizens evaluate different hypothetical differentiated integration arrangements, with varying decision-making procedures, using a conjoint experiment. We ask whether institutional arrangements can overcome citizens’ preference heterogeneity over differentiated integration, and thereby foster the legitimacy of a differentiated European Union. We find that while a majority of citizens care about the inclusiveness of differentiated integration arrangements, they also support limiting the number of veto points. Our analysis also reveals noteworthy differences across citizens with pro- and anti-European Union attitudes in the perceived fairness of differentiated integration arrangements.

The Russian invasion of Ukraine has thrust the issue of European Union and NATO enlargement back into the political spotlight. However, it remains uncertain whether established theoretical frameworks are still applicable in today's rapidly changing world. In response to this uncertainty, this debate section brings together five short reflection pieces, with a response from Frank Schimmelfennig, to assess the relevance of the theory of 'rhetorical action' in light of recent developments in European and international politics. How effectively does rhetorical action explain current EU and NATO enlargement processes, as well as broader forms of international cooperation? The authors find strong overall support for the theory's continued validity. However, they caution that the increasing politicisation of issues, the rising competition from populist, non-liberal forces, and the broader crisis of the Liberal International Order require more careful reflection and specification of the scope conditions that define the theory's limits.

This article maps and investigates public support for different types of differentiated integration (DI) in the European Union. We examine citizens’ preferences for DI using novel survey data from eight EU member states. The data reveals substantive differences in support for different types of DI. Factor analyses reveal two dimensions that seem to structure citizens’ evaluations of DI. The first dimension relates to the effect of DI on the European integration project, the second concerns the safeguarding of national autonomy. Citizens’ attitudes on this second dimension vary substantively across countries. General EU support is the most important correlate of DI support, correlating positively with the first and negatively with the second dimension. Our results underline that while citizens generally care about the fairness of DI, balancing out their different concerns can be a challenging political task.

Research on differentiated integration (DI) in the European Union (EU) has focused on the causes, conditions, and patterns of differentiation in European integration. By contrast, we know less about its effects on institutional outcomes and public support; moreover, alternatives to de jure DI in providing flexibility are still rarely accounted for. This introduction to the special issue takes stock of, and discusses omissions, in the current literature on DI. We propose an analytical framework, centering on efficiency and legitimacy, to study the effects of different types of DI. We use this framework to motivate the choice and assess the contributions of the articles selected for this special issue.

International solidarity is indispensable for coping with global crises; however, solidarity is frequently constrained by public opinion. Past research has examined who, on the donor side, is willing to support European and international aid. However, we know less about who, on the recipient side, is perceived to deserve solidarity. The article argues that potential donors consider situational circumstances and those relational features that link them to the recipients. Using factorial survey experiments, we analyse public support for international medical and financial aid in Germany during the COVID-19 pandemic. Our results show that recipient countries' situational need and control, as well as political community criteria, namely, group membership, adherence to shared values and reciprocity, played a crucial role in explaining public support for aid. Important policy implications result: on the donor side, fault-attribution frames matter; on the recipient side, honouring community norms is key to receiving aid.

Previous research emphasizes that individual economic status does not significantly influence support for redistribution within the European Union (EU). Instead, identity factors are often posited as the main causes. We study the interaction of these variables and synthesize various theories that all predict that heightened European identification leads to a weaker influence of economic status. In a large original survey fielded in 12 countries, we find that respondents' income and perceived relative position correlate negatively with their redistribution preferences, both on the national and the EU level, as predicted by economic accounts. We also replicate findings on the positive effect of identity variables and find some evidence for the predicted interaction. However, randomized information treatments aimed at altering perceptions of an individual's or their member state's relative economic position fail to impact on preferences and do not interact with identity variables. Overall, our findings point toward a possible but quantitatively very limited role of economic status and its interaction with identity in understanding EU redistribution preferences.

This chapter critically takes stock of methods and data sources used in the study of differentiated integration (DI). We first catalogue and exemplify prominent methods of DI research, before quantitatively tracing the usage of these methods over time. The analysis of a DI bibliography, spanning the period 1995–2020, reveals that DI predominantly has been a playground for qualitative research in the past. However, more recently, an upsurge of methodological pluralism becomes detectable in our data. We take this as an indication for a growing maturity of the field. Before concluding the chapter, we briefly introduce and discuss a number of datasets that are already used, or that may potentially be useable, in the study of DI.