Ever tighter union? Brexit, Grexit, and frustrated differentiation in the single market and Eurozone


Many European political leaders and observers have argued that the European Union’s multiple recent challenges call for more “differentiated integration.” At first glance, the EU may seem to lend itself quite well to such an approach, with already variegated memberships in the Euro area or Schengen borderless travel zone. What proponents of differentiation tend to overlook, however, is that the Union’s core commitments are not set up to permit much internal variation at all. Indeed, in the EU’s two flagship policy areas—the Single Market and the Eurozone—the defining institutional principles rule out differentiation to a striking degree. To substantiate this claim, we show that the rules in these areas are considerably more constraining of EU member states than are analogous federal constraints within the USA. We then highlight how these tightly limiting principles of EU economic governance have shaped recent negotiations with Greece in the Eurozone and the UK in the Single Market. While the EU’s core constraining principles make calls for differentiation all the more comprehensible, they also underscore that differentiated options may require rather fundamental change to the current institutional status quo.

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  1. 1.

    Montenegro and Kosovo use the euro; Iceland, Norway, and Liechtenstein are in the Single Market.

  2. 2.

    Fabbrini (2019). For a related discussion, see Schütze (2009).

  3. 3.

    See the website of the private American National Standards Institute. Its page on state variations (https://www.standardsportal.org/usa_en/key_information/state_level.aspx.) explains, “The hallmark of the United States standardization and conformity assessment systems is its decentralized nature. In large part, this defining characteristic is a product of the United States’ decentralized federal governmental structure organized to balance power with individual U.S. State governments.”

  4. 4.

    The Court has often suggested that it also employs a “balancing” logic to evaluate whether a restriction on commerce is justified by its local benefits, but Regan (1986) argues compellingly that this is so inconsistently applied that the effective logic focuses on purposeful protectionism.

  5. 5.

    These criteria are known as a “Gebhard test” in services, and are similar in goods.

  6. 6.

    See the Brookings Institution’s “tracker” of deregulation under Trump at https://www.brookings.edu/interactives/tracking-deregulation-in-the-trump-era/.

  7. 7.

    As of 2018, seven US states forego individual income taxes: Alaska, Florida, Nevada, South Dakota, Texas, Washington, and Wyoming. New Hampshire and Tennessee only tax income on capital investments, including dividends.

  8. 8.

    As quoted in Matthijs (2016: 375).

  9. 9.

    Greece’s gross GDP at market prices decreased by 27% between 2008 and 2015: http://appsso.eurostat.ec.europa.eu/nui/show.do?dataset=nama_10_gdpandlang=en.

  10. 10.

    From May 2015 to November 2015, the Eurobarometer measured an increase in support for membership in the Economic and Monetary Union.

  11. 11.

    As reported in the Financial Times: https://www.ft.com/content/9099a1a8-bcda-11e8-8274-55b72926558f.


  1. Arnett, G., and A. Galatsidas. 2015. Greek referendum: full results. The Guardian, 6 July, https://www.theguardian.com/world/ng-interactive/2015/jul/05/live-results-greek-referendum.

  2. Augenstein, D. (ed.). 2013. Integration through Law Revisited: The Making of the European Polity. London: Ashgate.

    Google Scholar 

  3. Barnard, C. 2008. Unravelling the Services Directive. Common Market Law Review 45: 323–394.

    Google Scholar 

  4. Barnier, M. 2017. cited in BBC News (2017) Brexit: UK to leave single market, says Theresa May. 17 January, https://www.bbc.co.uk/news/uk-politics-38641208.

  5. Barnier, M. 2018. Speech at the US Council on Foreign Relations. New York. Cited in Johnson, B. (2018) Farage vows return while Barnier reiterates indivisibility of EU’s four freedoms as Brussels reacts to Theresa May’s Brexit proposals. The Parliament Magazine, 11 July.

  6. BBC. 2014. EU migrant curbs should be ‘temporary’ says Major. 16 November, https://www.bbc.com/news/uk-politics-30073844.

  7. Blockmans, S. 2017. The uncertain future of the European Union. International Politics and Society, 3 March, https://www.ips-journal.eu/in-focus/europe-fears-europe-dreams/artikel/article/show/the-uncertain-future-of-the-european-union-1885/.

  8. Bork, R., and D. Troy. 2002. Locating the Boundaries: The Scope of Congress’s Power to Regulate Commerce. Harvard Journal of Law and Public Policy 25(3): 849–893.

    Google Scholar 

  9. Buchanan, J.M. 1965. An Economic Theory of Clubs. Economica 32(125): 1–14.

    Article  Google Scholar 

  10. Bundesministerium für Finanzen. 2015. Comments on the latest Greek proposals. 10 July.

  11. Buzbee, W. (ed.). 2008. Preemption Choice: The Theory, Law, and Reality of Federalism’s Core Question. New York: Cambridge University Press.

    Google Scholar 

  12. Cameron, D. 2013. EU speech at Bloomberg. London, 23 January.

  13. Cameron, D. 2014. JBC Staffordshire: Prime Minister’s speech. Staffordshire, 28 November.

  14. Cameron, D. 2015a. Speech at the European Council. Brussels, 26 June.

  15. Cameron, D. 2015b. A New Settlement for the United Kingdom in a Reformed European Union. Letter to Donald Tusk, 10 November.

  16. Cappelletti, M., M. Seccombe, and J. Weiler (eds.). 1986. Integration through Law: Europe and the American Federal Experience., vol. 1. Brussels: de Gruyter.

    Google Scholar 

  17. Conservatives. 2015. The Conservative Party Manifesto 2015.

  18. Davies, P. 1997. Posted Workers: Single Market or Protection of National Labour Law Systems. Common Market Law Review 34: 571–602.

    Article  Google Scholar 

  19. De Witte, D. 2007. “How Did Services Get to Bolkestein and Why?” EUI Working Paper Law 2007/20. Florence: European University Institute.

  20. Dyson, K., and M. Marcussen. 2010. Transverse Integration in European Economic Governance. Journal of European Integration 32(1): 17–39.

    Article  Google Scholar 

  21. Economist. 2017. Differentiate or bust: Europe’s future is multi-speed and multi-tier. 23 March, https://www.economist.com/special-report/2017/03/23/europes-future-is-multi-speed-and-multi-tier.

  22. Egan, M. 2015. Single Markets: Economic Integration in Europe and the United States. Oxford: Oxford University Press.

    Book  Google Scholar 

  23. Epstein, R., and M. Greve (eds.). 2007. Federal Preemption: States’ Powers, National Interests. Washington, D.C.: AEI Press.

    Google Scholar 

  24. Euro Summit. 2015. Euro Summit Statement. 12 July, http://www.consilium.europa.eu/media/20353/20150712-eurosummit-statement-greece.pdf.

  25. European Commission. 2015a. Statement on behalf of the European Commission by Jonathan Hill on the capital controls imposed by the Greek authorities. Press Release Database, 29 June.

  26. European Commission. 2015b. Standard Eurobarometer 83/84. http://ec.europa.eu/commfrontoffice/publicopinion/index.cfm/Survey/index#p=1andinstruments=STANDARD.

  27. European Commission. 2017. White Paper on the Future of Europe: Reflections and Scenarios for the EU27 by 2025. Brussels, 1 March, https://ec.europa.eu/commission/sites/beta-political/files/white_paper_on_the_future_of_europe_en.pdf.

  28. European Commission. 2018. Internal Market, Industry, Entrepreneurship and SMEs. https://ec.europa.eu/growth/about-us_en. Accessed 3 Aug 2018.

  29. European Commission, Hellenic Republic and Bank of Greece. 2015. Memorandum of Understanding. 19 August, https://ec.europa.eu/info/sites/info/files/01_mou_20150811_en1.pdf.

  30. European Commission, ECB and IMF. 2015. List which takes account of the proposals of the Greek authorities received on 8, 14, 22 and 25 June. 26 June 20h00.

  31. European Council. 2017. European Council (Art. 50) guidelines for Brexit Negotiations. 29 April, http://www.consilium.europa.eu/en/press/press-releases/2017/04/29/euco-brexit-guidelines/.

  32. Fabbrini, F. 2013. The Fiscal Compact, the “Golden Rule”, and the Paradox of European Federalism. Boston College International and Comparative Law Review 36(1): 1–38.

    Google Scholar 

  33. Fabbrini, S. 2019. Alternative Governance Models: ‘Hard Core’ in a Plural Europe. Comparative European Politics 17(2).

  34. Gotev, G. 2017. ‘Junker’s real scenario’ is multi-speed Europe. Euractiv, 1 March, https://europa.eu/newsroom/highlights/special-coverage/60th-anniversary-treaties-rome_en.

  35. Grice, A. 2013. David Cameron rushes in curbs on the rights of migrants to claim benefits to head off backbench revolt. Independent, 18 December, https://www.independent.co.uk/news/uk/politics/david-cameron-rushes-in-curbs-on-the-rights-of-migrants-to-head-off-backbench-revolt-9011458.html.

  36. Hatzopoulos, V. 2012. Regulating Services in the European Union. Oxford: Oxford University Press.

    Book  Google Scholar 

  37. Henning, R., and M. Kessler. 2012. Fiscal Federalism: US History for Architects of Europe’s Fiscal Union.

  38. Bruegel Essay and Lecture Series. http://bruegel.org/wp-content/uploads/imported/publications/essay_fiscfed_web_01.pdf.

  39. HM Government. 2018. Statement from HM Government. Chequers, 6 July.

  40. Hoffmann, L. 2011. Land of the Free, Home of the (Un)regulated: A Look at Market-building and Liberalization in the EU and the US. Eugene: University of Oregon.

    Google Scholar 

  41. International Monetary Fund. 2015. Press Release: Statement by the IMF on Greece. Press Release No.15/310, June 30.

  42. Jabko, N. 2006. Playing the Market: A Political Strategy for Uniting Europe, 1985–2005. Ithaca: Cornell University Press.

    Google Scholar 

  43. Jacoby, W. 2015. Europe’s New German Problem: The Timing of Politics and the Politics of Timing. In The Future of the Euro, ed. M. Matthijs and M. Blyth, 187–209. New York: Oxford University Press.

    Google Scholar 

  44. Johnson, B. 2016. I cannot stress too much that Britain is part of Europe—and always will be. Telegraph, 26 June.

  45. Julander, T. 2002. State Resident Preference Statutes and the Market Participant Exemption to the Dormant Commerce Clause. Whittier Law Review 24: 541–593.

    Google Scholar 

  46. Kelemen, R.D., and S. Schmidt. 2011. The European Court of Justice and legal integration: perpetual momentum? Journal of European Public Policy 19(1): 1–7.

    Article  Google Scholar 

  47. Kohler, W., and G. Müller. 2017. Brexit, the Four Freedoms, and the Indivisibility Dogma. Voxeu.org, posted 8 November 2017.

  48. Kwasniewski, N. 2015. Vorschläge der Euro-Gruppe: Der Katalog der Grausamkeiten. Spiegel Online, 12 December, http://www.spiegel.de/wirtschaft/soziales/griechenland-euro-gruppe-legt-extrem-harte-forderungen-vor-a-1043306.html.

  49. Lambert, H. 2015. Exclusive: Yanis Varoufakis opens up about his five month battle to save Greece. New Statesman, 13 July, https://www.newstatesman.com/world-affairs/2015/07/exclusive-yanis-varoufakis-opens-about-his-five-month-battle-save-greece.

  50. Majone, G. 2014. Rethinking the Union of Europe Post-Crisis: Has Integration Gone too far?. Cambridge: Cambridge University Press.

    Book  Google Scholar 

  51. Matthijs, M. 2013. David Cameron’s Dangerous Game. Foreign Affairs 92 (5), September/October: 10–16.

  52. Matthijs, M. 2016. Powerful Rules Governing the Euro: The Perverse Logic of German Ideas. Journal of European Public Policy 23(3): 375–391.

    Article  Google Scholar 

  53. Matthijs, M. 2017a. Europe After Brexit. Foreign Affairs 96(1): 85–95.

    Google Scholar 

  54. Matthijs, M. 2017b. Integration at What Price? The Erosion of National Democracy in the Euro Periphery. Government and Opposition 52(2): 266–294.

    Article  Google Scholar 

  55. Matthijs, M., and M. Blyth (eds.). 2015a. The Future of the Euro. New York: Oxford University Press.

    Google Scholar 

  56. Matthijs, M., and M. Blyth. 2018. When Is It Rational to Learn the Wrong Lessons? Technocratic Authority, Social Learning, and Euro Fragility. Perspectives on Politics 16(1): 110–126.

    Article  Google Scholar 

  57. May, T. 2017. Lancaster House Speech. London, 17 January.

  58. May, T. 2018. Mansion House Speech on future UK-EU relations. London, 2 March.

  59. McSmith, A. 2014. Cameron is warned ‘no possibility’ of UK reducing immigration and that bid to bring in quota on migrant workers would be illegal. Independent, 19 October, https://www.independent.co.uk/news/uk/politics/eu-chief-warns-no-possibility-of-uk-reducing-immigration- as-cameron-is-warned-quota-on-migrant-9804464.html.

  60. Merkel, A. 2016. Merkel: Es wird keine Rosinenpickerei geben. Bundestag, 28 June. https://www.bundestag.de/dokumente/textarchiv/2016/kw26-regierungserklaerung-brexit/429386.

  61. Merler, S. 2015. Greece Budget Update. Brussels: Bruegel. 16 July. http://bruegel.org/2015/07/greece-budget-update/.

  62. Moravcsik, A. 1998. The Choice for Europe. Ithaca: Cornell University Press.

    Google Scholar 

  63. Moravcsik, A. 1999. A New Statecraft? Supranational Entrepreneurs and International Cooperation. International Organization 53(2): 267–306.

    Article  Google Scholar 

  64. Moravcsik, A. 2002. Reassessing Legitimacy in the European Union. Journal of Common Market Studies 40(4): 603–624.

    Article  Google Scholar 

  65. Minister of Finance Hellenic Republic. 2015a. Letter requesting stability support, 8 July, https://www.tagesschau.de/antrag-griechenland-101.pdf.

  66. Minister of Finance Hellenic Republic. 2015b. Greece: Prior Actions, Policy Commitments and Actions to be taken in consultation with EC/ECB/IMF staff. 9 July, http://www.wsj.com/public/resources/documents/GreekProposals070915.pdf.

  67. Ministry of Finance Hellenic Republic. 2015c. A Policy Framework for Greece’s Fiscal Consolidation, Recovery and Growth. 11 May.

  68. Ministry of Finance Hellenic Republic. 2015d. Ending the Greek Crisis: Structural Reforms, Investment-led Growth and Debt Management. 11 June.

  69. Nicolaïdis, K., and S. Schmidt. 2007. Mutual Recognition ‘On Trial’: The Long Road to Services Liberalization. Journal of European Public Policy 14(5): 717–734.

    Article  Google Scholar 

  70. Office for National Statistics. 2018. Migration Statistics Quarterly Report: July 2018.

  71. Newman, A. 2015. The Reluctant Leader: Germany’s Euro Experience and the Long Shadow of Reunification.

  72. Matthijs, M., and M. Blyth (eds.). 2015. The Future of the Euro. New York: Oxford University Press, 117–135.

  73. Parker, G., and A. Barker. 2018. May Brexit speech keeps government intact but faces frosty EU response.

  74. Financial Times, 2 March, https://www.ft.com/content/abbd4e22-1e2d-11e8-956a-43db76e69936.

  75. Parsons, C. 2003. A Certain Idea of Europe. Ithaca: Cornell University Press.

    Google Scholar 

  76. Regan, D. 1986. The Supreme Court and Protectionism: Making Sense of the Dormant Commerce Clause. Michigan Law Review 84(6): 1091–1287.

    Article  Google Scholar 

  77. Russack, S. 2017. How is Juncker’s ‘last-chance Commission’ faring at mid-term? CEPS European Policy Analysis, Issue 2017:4, https://www.ceps.eu/system/files/SR_JunckerCommission_0.pdf.

  78. Sandbu, M. 2015. Europe’s Orphan: The Future of the Euro and the Politics of Debt. Princeton: Princeton University Press.

    Book  Google Scholar 

  79. Schimmelfennig, F. 2019. The Choice for Differentiated Europe: An Intergovernmentalist Theoretical Framework. Comparative European Politics 17(2).

  80. Schimmelfennig, F., and T. Winzen. 2014. Instrumental and Constitutional Differentiation in the European Union. Journal of Common Market Studies 52(2): 354–370.

    Article  Google Scholar 

  81. Schmidt, V. 2019. The Future of Differentiated Integration: a ‘Soft-Core,’ multi-clustered Europe of Overlapping Policy Communities. Comparative European Politics 17(2).

  82. Schütze, R. 2009. From Dual to Cooperative Federalism. Oxford: Oxford University Press.

    Book  Google Scholar 

  83. Sinn, H.W. 2017. Für Deutschland ist der Brexit verheerend. Frankfurter Allgemeine Zeitung, 16 March 2017.

  84. Spiegel. 2014. Rote Linie, roter Kopf. Issue 45/2014.

  85. Stubb, A. 1996. A Categorisation of Differential Integration. Journal of Common Market Studies 34(2): 283–295.

    Article  Google Scholar 

  86. Syriza. 2014. The Thessaloniki Programme. 13 September, https://www.syriza.gr/article/id/59907/SYRIZA—THE-THESSALONIKI-PROGRAMME.html.

  87. Tate, J. 2001. National varieties of standardization. In Varieties of Capitalism: The Institutional Foundations of Comparative Advantage, ed. P. Hall and D. Soskice, 442–473. New York: Oxford University Press.

    Google Scholar 

  88. Traynor, I. 2012. David Cameron’s moves could make EU fall apart, says Herman Van Rompuy. The Guardian, 27 December, https://www.theguardian.com/world/2012/dec/27/david-cameron-eu-herman-van-rompuy.

  89. Visegrad Group. 2015. Joint Statement of the Visegrad Group Countries. Brussels, 7 December.

  90. Weiler, J. 2000. Epilogue: Towards a Common Law of International Trade. In The EU, the WTO, and the NAFTA: Towards a Common Law of International Trade, ed. J. Weiler, 201–229. Oxford: Oxford University Press.

    Google Scholar 

  91. Winzen, T. 2016. From Capacity to Sovereignty: Legislative Politics and Differentiated Integration in the European Union. European Journal of Political Research 55(1): 100–119.

    Article  Google Scholar 

  92. Waterfield, B. 2013. José Manuel Barroso: David Cameron’s plan to claw back powers from the EU is ‘doomed to failure.’ Telegraph, 2 October, https://www.telegraph.co.uk/news/worldnews/europe/eu/10350956/Jose-Manuel-Barroso-David-Camerons-plan-to-claw-back-powers-from-the-EU-is-doomed-to-failure.html.

  93. Withnall, A. 2014. Iain Duncan Smith wants two-year ban on immigrant welfare—but Brussels says EU will block attempts to rewrite rules. Independent, 12 January, https://www.independent.co.uk/news/uk/politics/iain-duncan-smith-wants-two-year-ban-on-immigrant-welfare-but-brussels-says-eu-will-block-attempts-9054215.html.

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The authors would like to thank Vivien Schmidt, Sergio Fabbrini, Mark Pollack, Dan Kelemen, Chris Bickerton, Fritz Scharpf, Jolyon Howorth, Erik Jones, Frank Schimmelfennig, as well as two anonymous reviewers, for very helpful comments on previous versions of this paper. The usual disclaimer applies: the authors remain solely responsible for any errors or omissions.

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Matthijs, M., Parsons, C. & Toenshoff, C. Ever tighter union? Brexit, Grexit, and frustrated differentiation in the single market and Eurozone. Comp Eur Polit 17, 209–230 (2019). https://doi.org/10.1057/s41295-019-00165-6

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  • Differentiation
  • European Union
  • Eurozone
  • Integration
  • Single market
  • United States