The European Union: Integration and Enlargement

Co-edited with Anand Menon, Jonathan Slapin. 

Routledge, 2014.

The Power of the European Court of Justice 

Co-edited with Susanne Schmidt. Routledge, 2012. 

Eurolegalism: The Transformation of Law and Regulation in the European Union 

Cambridge, MA: Harvard University Press, 2011 [Replication Data]

The Oxford Handbook of Law and Politics 

Co-edited with Keith Whittington and Greg Caldeira. 

Oxford University Press, 2008. 

The Rule of Federalism: The Institutions and Regulatory Politics in the EU and Beyond

Harvard University Press, 2004

Selected Articles in Political Science Journals

This article dismantles the myth that the EU’s failure to respond adequately to the rise of autocratic member governments has been due to its lack of adequate tools. The EU has used this excuse repeatedly to justify engaging in what Laurent Pech calls a new instrument creation cycle – reacting to attacks on democracy and the rule of law not by deploying existing tools but by wasting time creating new ones. The repetition of this cycle has resulted in the creation of a Rule of Law Rube Goldberg machine – a redundant assemblage of mostly useless instruments ostensibly designed to help the EU address backsliding. The pointlessness of many of these tools is underscored when we look closely at the few simple but potentially powerful, MacGyver-like tools that the EU has had at its disposal all along, but which EU leaders have failed to use robustly to defend democracy.

"Seeing Europe like a state," article with Kathleen McNamara, Journal of European Public Policy, 29(12) (2022), pp. 1916-1927.

In writing ‘State-building and the European Union’ we hoped to open up a conversation. We are gratified at how the thoughtful contributions of the Debate Section participants usefully push the debate forward. We stress that our story of state-building and the EU is about contingent causal processes within specific cases, not universal laws. This allows for a series of rich research questions, posed by the participants, around how different types of security threats may play out in the EU, interacting with other political logics. It thus fully demonstrates how scholarly understanding of the EU is enhanced by historical comparison with state-building, illuminating similarities and differences to earlier episodes of political consolidation. Approaching the EU through the lens of state-building not only holds benefits for EU studies, but also for the study of state-building itself in incorporating novel processes of the construction of political authority in the twenty-first century.

"State-building and the European Union: Markets, War, and Europe's Uneven Political Development," article with Kathleen McNamara, Comparative Political Studies, 55(6) (2021), pp. 963-991. DOI: 10.1177/00104140211047393

The European Union’s institutional development is highly imbalanced. It has established robust legal authority and institutions, but it remains weak or impotent in terms of its centralization of fiscal, administrative, and coercive capacity. We argue that situating the EU in terms of the history of state-building allows us to better understand the outcomes of EU governance. Historically, political projects centralizing power have been most complete when both market and security pressures are present to generate state formation. With the EU, market forces have had a far greater influence than immediate military threats. We offer a preliminary demonstration of the promise of this approach by applying it to two empirical examples, the euro and the Schengen area. Our analysis suggests that the EU does not need to be a Weberian state, nor be destined to become one, for the state-building perspective to shed new light on its processes of political development.

“Epilogue: A Note of Caution on Differentiated Integration,"Swiss Political Science Review, 27(3) (2021), pp.672-681.

This epilogue to the special issue of the Swiss Political Science Review on “Democratic Challenges of Differentiated (Dis)Integration” raises some notes of caution about differentiated integration in the European Union (EU). While the articles in this special issue identify challenges concerning differentiated integration, they generally view it in a positive light as a set of institutional arrangements that is likely to enhance the legitimacy and democratic accountability of the EU. This epilogue calls into question some of the main benefits widely associated with differentiated integration and emphasizes instead its dangers. The epilogue underlines some reasons why differentiated integration may be problematic from a democratic standpoint and explains why, if taken to an extreme, differentiated integration could even encourage the disintegration of the EU.

“Failing Forward? Crises and Patterns of European Integration,” with Erik Jones and Sophie Meunier, Journal of European Public Policy, 28(10) (2021), pp. 1519-1536.

In our contribution to this new wave of integration theory (Jones et al., 2016), we bridged the liberal institutionalist and neo-functionalist traditions to argue that in some circumstances European integration proceeded through a pattern of failing forward: in an initial phase, lowest common denominator intergovernmental bargains led to the creation of incomplete institutions, which in turn sowed the seeds of future crises, which then propelled deeper integration through reformed but still incomplete institutions – thus setting the stage for the process to move integration forward.

“The European Union's authoritarian equilibrium,” Journal of European Public Policy, 27(3) (2020), pp.481-499.

While the European Union (EU) professes a commitment to liberal democracy, in recent years it has allowed some member governments to backslide toward competitive authoritarianism. The EU has become trapped in an ‘authoritarian equilibrium’ underpinned by three factors. First, the EU's half-baked system of party politics and its ingrained reluctance to interfere in the domestic politics of its member states help shield national autocrats from EU intervention. Second, funding and investment from the EU helps sustain these regimes. Third, the free movement of persons in the EU facilitates the exit of dissatisfied citizens, which depletes the opposition and generates remittances, thereby helping these regimes endure. While more fully developed democratic federations have the capacity to eventually steer autocratic member states back toward democracy, the EU appears to be stuck in an autocracy trap.

“Is Differentiation possible in rule of law?,” Comparative European Politics, 17(2019), Special Issue on “Imagining the Future of Europe,” edited by Sergio Fabbrini and Vivien Schmidt, pp. 246-60.

The European Union (EU) is a community based on the rule of law. EU member states have committed themselves to uphold the rule of law and to respect the primacy of EU law. Yet today, the EU legal order is threatened by the emergence of increasingly autocratic member state governments, particularly those in Hungary and Poland, who routinely violate the fundamental rule of law principles on which the EU is based. This article assesses whether the model of differentiated integration can be applied to help the EU address this rule of law crisis. In recent years, many analysts have called on the EU to embrace a model of differentiated integration as a way to address its many challenges, and some have suggested that versions of differentiation might help the EU resolve tensions with its member states concerning the rule of law. By contrast, this article will argue that differentiation in the rule of law and the theory of constitutional pluralism that some use to justify it are neither normatively desirable nor practically feasible models. In short, we must reject differentiated integration when it comes to rule of law.

"The Political Geography of Legal Integration: Visualizing Institutional Change in the European Union," with Tommaso Pavone. World Politics (2018), doi: 10.1017/S0043887118000011

 This article explores how the EU’s legal order has developed and expanded over space and time. Over the past six decades, the architects of the EU legal order have layered new supranational institutions atop existing national legal orders while seeking to convert national judiciaries into EU courts. Specifically, we analyze how this process has been affected by its interaction with the preexisting judicial orders of its member states. In so doing, we show how these institutional developments not only have a temporal dimension that can be uncovered via time-series analysis, process tracing, and comparative historical analysis,8 but also have a spatial structure that can be visualized and analyzed through mapping.9 By theorizing and empirically evaluating the political geography of European legal integration, our approach demonstrates how scholars can literally “see” historical institutionalism at work.

"Reconceptualizing EU Regulatory Networks: A response to Blauberger and Rittberger," with Andrew Tarrant, Regulation & Governance, (2017), 2 March, DOI: 10.1111/rego.12135.

This article responds to Michael Blauberger and Berthold Rittberger's article “Conceptualizing and theorizing EU regulatory networks,” published in Regulation & Governance in 2015. Blauberger and Rittberger challenged our previous work on the politics of Eurocracy, disputing our argument that political considerations, not functional ones, explain the choice of bureaucratic structure in the European Union (EU). Blauberger and Rittberger suggest that functional considerations do indeed explain why policymakers sometimes prefer governance through European Regulatory Networks rather than through more centralized EU agencies, and argue that we have misunderstood the preferences of EU legislative principals. In this article, we argue that there are significant flaws in Blauberger and Rittberger's analysis on both theoretical and empirical grounds. We show that a proper interpretation of developments in both telecoms and competition lends support to our theoretical claims and not those offered by Blauberger and Rittberger.

This article argues for a radical recasting of the European Union democratic deficit debate. Critics have long argued that the EU suffers from a democratic deficit and that growing EU power undermines national democracy. But recent backsliding on democracy and the rule of law in Hungary and Poland reminds us that grave democratic deficits can also exist at the national level in member states and that the EU may have a role in addressing them. This article will place the EU’s struggles with democratic deficits in its member states in comparative perspective, drawing on the experience of other democracies that have struggled with pockets of subnational authoritarianism. Comparative analysis suggests that considerations driven by partisan politics may allow local pockets of autocracy to persist within otherwise democratic political unions.

"Can Courts Rescue National Democracy? Judicial Safeguards against Democratic Backsliding in the EU," with Michael Blauberger, Journal of European Public Policy, 24,3 (2017).

This article explores the potential efficacy and limitations of judicial mechanisms as tools to combat democratic backsliding in European Union (EU) member states. The article argues that more can be done to maximize the effectiveness of existing judicial tools, such as infringement proceedings brought to the European Court of Justice (ECJ) by the Commission and private enforcement litigation in national courts. At the same time, we highlight risks inherent in many proposals for novel judicial tools to defend national democracy. We conclude that despite their importance, judicial safeguards alone – whether existing ones or novel proposals – will not suffice to stop democratic backsliding by a determined national government: if the Union is to rein in such attacks on its core values, heads of government and other EU leaders will have to intervene politically as well.

"Trojan Horses in EU Foreign Policy," with Mitchell Orenstein. Journal of Common Market Studies, 55,1 (2017), pp. 87-102.

Why has the European Union been able to craft a unified sanctions policy against Russia but failed to rein in Russia's ‘Trojan horses’ within the EU that pursue pro-Putin foreign policies? We argue that the EU suffers from a specific type of disaggregation in its foreign and security policy. While the EU's Common Foreign and Security Policy has increased its capacities over time, the EU still lacks the power to prevent Member States from pursuing their own independent policies. In the face of the Ukraine crisis, for instance, the EU marshaled a surprisingly strong sanctions regime, but could not prevent Member States from pursuing divergent pro-Russia policies, such as signing new energy deals or granting port access for Russian naval forces. As EU foreign and security powers grow, foreign powers face increasing incentives to cultivate Trojan horses among the EU Member States.

"Mapping European Law," with Tommaso Pavone, Journal of European Public Policy, 23, 8 (2016), pp.1118-1138.

This article constitutes the first systematic effort to promote a spatial and a subnational turn in the study of EU legal integration by demonstrating how geospatial methods and the selection of a subnational unit of analysis can improve our understanding of the use of the preliminary reference procedure. We conduct a theory-testing case study leveraging an original dataset of all references submitted by Italian courts from 1964 through 2013 and utilize geographic information systems (GIS) technology to analyze subnational patterns in reference activity. We use these data to evaluate whether several existing hypotheses explain recent subnational variation in reference rates. We uncover several illuminating findings. First, although population levels and domestic litigiousness best explain variation in reference rates, there is evidence that the domestic litigation effect is subnationally heterogeneous. Second, although use of the reference procedure has diffused since the 1960s, subnational reference rates are spatially clustered by issue area.

"Failing Forward? The Euro Crisis and the Incomplete Nature of European Integration," with Erik Jones and Sophie Meunier, (2016), Comparative Political Studies, 49, 7(2016), pp.1010-1034.

The European Union (EU) project of combining a single market with a common currency was incomplete from its inception. This article shows that the incompleteness of the governance architecture of Europe’s Economic and Monetary Union (EMU) was both a cause of the euro crisis and a characteristic pattern of the policy responses to the crisis. We develop a “failing forward” argument to explain the dynamics of European integration using recent experience in the eurozone as an illustration: Intergovernmental bargaining leads to incompleteness because it forces states with diverse preferences to settle on lowest common denominator solutions. Incompleteness then unleashes forces that lead to crisis. Member states respond by again agreeing to lowest common denominator solutions, which address the crisis and lead to deeper integration. To date, this sequential cycle of piecemeal reform, followed by policy failure, followed by further reform, has managed to sustain both the European project and the common currency. However, this approach entails clear risks. Economically, the policy failures engendered by this incremental approach to the construction of EMU have been catastrophic for the citizens of many crisis-plagued member states. Politically, the perception that the EU is constantly in crisis and in need of reforms to salvage the union is undermining popular support for European integration.

Selected Articles in Law Journals

“Appeasement, ad infinitum,” Maastricht Journal of European and Comparative Law, 29, 2 (2022), pp. 177-181.

Never underestimate the European Commission’s willingness to appease Europe’s pet autocrats.1 While the EU has made an impressive show of unity in standing up to the murderous dictator Vladimir Putin in response to his unprovoked invasion of Ukraine, EU leaders continue to refuse to stand up to the softer autocrats in their own ranks. The capacity of the von der Leyen Commission (and of Commissions before it) to contrive excuses for refusing to enforce the EU rule of law norms that all Member States have committed to respect is something awesome to behold. The excuses keep changing, but the procrastination and appeasement are consistent

"The Uses and Abuses of Constitutional Pluralism: Undermining the Rule of Law in the Name of Constitutional Identity in Hungary and Poland,” with Laurent Pech, Cambridge Yearbook of European Legal Studies, 21 (2019), pp. 59–74 doi:10.1017/cel.2019.11

This article explains why autocrats love constitutional pluralism and constitutional identity. Though these concepts were developed by scholars and jurists with the best of intentions in mind, we explain why they are also attractive to and inherently prone to abuse by autocrats. We then describe how the regimes in Hungary and Poland have made use of these concepts in their drive to consolidate autocracy. We conclude that given the dangers inherent in constitutional pluralism and its susceptibility to abuse, it should be replaced with a more traditional understanding of the primacy of EU law.

This article analyzes how the judicial politics sparked by the European Union's (EU) legal development have evolved over time. Existing studies have traced how lower national courts began cooperating with the European Court of Justice (ECJ) to apply EU law because this empowered them to challenge government policies and the decisions of their domestic judicial superiors. We argue that the institutional dynamics identified by this ‘judicial empowerment thesis’ proved self-eroding over time, incentivizing domestic high courts to reassert control over national judicial hierarchies and to influence the development EU law in ways that were also encouraged by the ECJ. We support our argument by combining an analysis of a dataset of cases referred to the ECJ with comparative case study and interview evidence. We conclude that while these evolving judicial politics signal the institutional maturation of the EU legal order, they also risk weakening the decentralized enforcement of European law.

"On the unsustainability of constitutional pluralism: European Supremacy and the Survival of the Eurozone," Maastricht Journal of European & Comparative Law, 23,1 (2016), pp.136-150.

For years, the Court of Justice of the European Union (Court of Justice) and national constitutional courts – particularly the German Federal Constitutional Court (Bundesverfassungsgericht; FCC) – have engaged in what developmental psychologists might term ‘parallel play’. The courts have played alongside each other, but not with each other. They have shared an interest in the same object (ultimate legal supremacy), and each has seen that object as its own. Many EU law scholars have celebrated this unsettled state of affairs, labelling it ‘constitutional pluralism’. But constitutional pluralism is unsustainable, and just as children grow out of parallel play, so too must Europe's courts. The FCC's reference to the Court of Justice in the Gauweiler case not only has profound implications for the survival of the Eurozone, but the case also seems to signal the end of an era: Europe's two most powerful courts must finally confront the incompatibility of their positions on the issue of Kompetenz-Kompetenz.

"The Court of Justice of the European Union in the Twenty-first Century," Law & Contemporary Problems, 79 (2016), pp.117-140.

Although the European Court of Justice (ECJ)'s authority is in many respects more extensive than ever before, the Court faces a number of new risks in its external context and it must tread carefully as its terrain grows more treacherous. Part II of this article analyzes the impact of geopolitical context on the development of the Court’s authority. This article shows that the early Court benefited from a very supportive geopolitical context, but recent changes have rendered its geopolitical context more threatening. Part III analyzes how the EU’s initial focus on the single market as a core subject matter supported the extension of its authority and how the spread of the Court’s jurisdiction to more controversial subject matters poses new challenges to this authority. Part IV focuses on the ECJ’s constituencies, highlighting the impact of member governments, national courts, and the broader European legal field on the development of the Court’s authority. In particular, recent changes in the ECJ’s constituencies context present the Court with new risks. 

"The United States, the European Union and International Environmental Law," with Tim Knievel, 13,4 (2015) I-CON: International Journal of Constitutional Law, pp.945-65.

In recent years, the United States has lagged behind the European Union in its ratification and implementation of major multilateral environmental agreements (MEAs). The development represents something of a role reversal between the US and the EU, given that the US had previously acted as the primary driver behind the adoption of most MEAs since the 1970s, with the EU largely following the American lead. Some have cited the US reluctance to engage on recent major MEAs as evidence of a diminishing American commitment to international environmental law, given prominent domestic political opposition to agreements like the Kyoto Protocol and the Convention on Biological Diversity. This position overlooks the enduring US commitment to previously ratified MEAs, and its general compliance with other major agreements that it has yet to formally ratify. Furthermore, while the EU has clearly become a major player in the realm of international environmental law, its embrace of major MEAs is driven primarily by domestic economic interests more than any abstract commitment to international law as such. We therefore argue that varying levels of commitment to substantive environmental policy goals at the domestic level, rather than varying levels of commitment to international law, may best explain US and EU positions concerning international environmental policy.

Selected Book Chapters and Articles in Non-Peer Reviewed Journals

“Defending Democracy in EU Member States: Beyond Article 7 TEU,” with Kim Lane Scheppele. In EU Law in Populist Times, edited by Francesca Bignami, 2020, pp.413- 456.

Commitment for Cowards: Why the judicialization of austerity is bad policy and even worse politics,” In Constitutions in Times of Financial Crisis, Tom Ginsburg, Mark Rosen, and Georg Vanberg and (eds.), Cambridge University Press, 2019, pp. 146- 62.

Federalism and European Integration,” In European Integration Theories, Antje Wiener, Tanja Börzel and Thomas Risse, eds., Oxford University Press, 2019, pp. 27- 42.

"The Dangers of Constitutional Pluralism," In Research Handbook on Pluralism and EU law, edited by Gareth Davies and Matej Avbelj, Edward Elgar, 2018, pp.392-403.

"Eurolegalism and the Better Regulation Agenda," In Sacha Garben and Ingo Govaere (eds.), The EU Better Regulation Agenda: A Critical Assessment, Hart Publishing, 2018, pp.205-215.

"Assessing the Transformation of Europe: A View from Political Science," with Alec Stone Sweet. In Miguel Maduro and Marlene Wind, eds, The Transformation of Europe: Twenty-Five Years On, Cambridge University Press, 2017, pp.193-205.

"Kagan's Atlantic Crossing: Adversarial legalism, Eurolegalism and cooperative legalism in European regulatory style," with Francesca Bignami. In Varieties of Legal Order, Thomas Burke and Jeb Barnes (eds.), Routledge, 2017, pp.81-97.

"Understanding the European Court's Political Power," with Karen Alter. In Key Controversies in European Integration, Andreas Dur and Hubert Zimmermann (eds.), Palgrave 2017, pp.81-90.

"European States in Comparative Perspective," In Oxford Handbook of Historical Institutionalism, Orfeo Fioretos, Tulia Falleti & Adam Sheingate (eds.), Oxford University Press, 2016, pp. 391-402.

"EU Regulation," In The Elgar Research Handbook on Comparative Law and Regulation, Francesca Bignami & David Zaring (eds.), Edward Elgar, 2016, pp.73-91.

"The Impact of the CJEU on the European Law Enforcement Architecture," In The Transformation of Enforcement, Hans Micklitz and Andrea Wechsler (eds.), Hart Publishing, 2016, pp. 163-178.

"Towards a New Constitutional Architecture in the European Union?," In What Form of Government for the European Union and the Eurozone?, Federico Fabbrini, Ernst Ballin and Han Somsen (eds.), Hart Publishing, 2015, pp.197-216.

"Selection, Appointment and Legitimacy: A Political Perspective," In Selecting Europe's Judges, edited by Michal Bobek, Oxford University Press, 2015, pp.244-258.

Selected Work in Progress

The European Law State, book project.

“Out of Sight Out of Mind? Voter Attitudes about Cooperation with Radical Parties in Europe,” with Jonathan Slapin, Michele Fenzl and Pit Rieger, manuscript under review.

"Federalism and Democratic Backsliding in Comparative Perspective,” with Robert R. Kaufman and Burcu Kolcak, manuscript.

"Where Have the Guardians Gone? Law Enforcement and the Politics of Supranational Forbearance in the European Union,” With Tommaso Pavone. (December 27, 2021).

Available at SSRN: or

Why would a supranational law enforcer suddenly refrain from wielding its powers? We theorize the supranational politics of forbearance – the deliberate under-enforcement of the law – and distinguish them from domestic forbearance. We explain why an exemplary supranational enforcer – the European Commission – became reluctant to launch infringements against European Union member states. While the Commission’s legislative role as “engine of integration” has been controversial, its enforcement role as “guardian of the Treaties” has been viewed as less contentious. Yet after 2004, infringements launched by the Commission plummeted. Triangulating between infringement statistics and elite interviews, we trace how the Commission grew alarmed that aggressive enforcement was jeopardizing intergovernmental support for its policy proposals. By embracing dialogue with governments over robust enforcement, the Commission sacrificed its role as guardian of the Treaties to safeguard its role as engine of integration. Our analysis holds broader implications for the study of forbearance in international organizations.

“Pecunia non olet? The Political Economy of Financial Flows into Democratic Backsliders,” with Julia Gray and Terence Teo, manuscript being prepared for submission.