1 See The Future of the EU: Two-speed Europe, or Two Europes?, The Economist, Nov. 10, 2011, available at http://www.economist.com/blogs/charlemagne/2011/11/future-eu (quoting a speech delivered by Nicolas Sarkozy on November 8, 2011).Google Scholar

2 See Tina Hildebrandt & Heinrich Wefing, Vergesst Diese EU, Zeit Online, Nov. 11, 2011, http://www.zeit.de/2011/46/Interview-Fischer (quoting an interview with Joschka Fischer).Google Scholar

3 Id. Google Scholar

4 Piris, Jean-Claude, The Future of Europe: Towards a Two-Speed EU? (2012).Google Scholar

5 See Débat: Une Europe à Deux Vitesses?, Le Monde, Nov. 4, 2011, available at http://www.lemonde.fr/idees/ensemble/2011/11/04/vers-une-europe-a-deux-vitesses_1598213_3232.html (containing different perspectives presented in a special debate section of the Le Monde).Google Scholar

6 Fear of a Two-Speed Europe: Britain Vetoes Changes to EU Treaties, Der Spiegel Online, Dec. 9, 2011, http://www.spiegel.de/international/europe/0,1518,802674,00.html.Google Scholar

7 Freedland, Jonathan, The Two-Speed Europe Is Here, with UK Alone in the Slow Lane, The Guardian, December 9, 2011), http://www.guardian.co.uk/world/2011/dec/09/jonathan-freedland-two-speed-europe.Google Scholar

8 Walker, Neil, Sovereignty and Differentiated Integration in the European Union, 4 Eur. L.J. 355, 374 (Dec. 1998).Google Scholar

9 See Helen Wallace & Wallace, William, Flying Together in a Larger and More Diverse European Union 27 (1995) (providing a comprehensive view of denominations of this phenomenon).Google Scholar

10 See Walker, , supra note 8, at 374; Sandra Marco Colino, Towards Greater Flexibility or Deadlock? The Progress of European Integration Since the Introduction of Enhanced Cooperation, The Federal Trust for Education and Research, Online Paper 24/04, at 7 (Sept. 1, 2004).Google Scholar

11 See Alexander C-G. Stubb, A Categorization of Differentiated Integration, 34 J. Common Mkt. Studs. 283, 283 (1996) (providing an overview of a variety of conceptions of differentiated integration).Google Scholar

12 Id. at 285; see also Wallace & Wallace, supra note 9, at 27.Google Scholar

13 Avbelj, Matej, Revisiting Flexible Integration in Times of Post-Enlargement and the Lustration of EU Constitutionalism, 4 Croat. Y.B. Eur. L. & Pol'y 132, 132 (2008).Google Scholar

14 Id. Google Scholar

15 Those explicitly authorized by the primary EU law comprise, first, legislative acts of different regulatory intensity, regulations and directives, whose purpose is either unification or merely harmonization of national laws.Google Scholar

16 Consolidated Version of The Treaty on the Functioning of the European Union Art. 288, Mar. 30, 2010, 2010 O.J. (C 83) 171 [hereinafter TFEU].Google Scholar

17 Vos, See Ellen, Differentiation, Harmonisation and Governance, in The Many Faces of Differentiation in EU Law 145, 147–49 (Bruno De Witte, Dominik Hanf & Ellen Vos eds., 2001) (providing an overview); Francesco de Cecco, Room to Move? Minimum Harmonization and Fundamental Rights, 43 Common Mkt. L. Rev. 9, 9 n.1 (2006). Minimum harmonization is provided for in the EC Treaty art. 137(5) (as in effect 2002) (now TFEU art. 153) (pertaining to social policy); EC Treaty art. 153(3) (as in effect 2002) (now TFEU art. 169) (pertaining to consumer protection); EC Treaty art. 174–176 (as in effect 2002) (now TFEU art. 191–193) (pertaining to environmental protection); and in—a rather different—EC Treaty art. 95(4)–(9) (as in effect 2002) (now TFEU art. 114(4)–(9)) (pertaining to Internal Market). Minimum harmonization may also be based on a Community secondary legislation, either expressly or by implication. See Case C-11/92, The Queen v. Sec'y of State for Health, ex parte Gallaher Ltd. et al., 1993 E.C.R. I-3545 (discussing the latter possibility).Google Scholar

18 See Weatherill, Stephen, Pre-emption and Competence in a Wider and Deeper Union, in Law and Integration in the European Union 135, 161 (1995) (discussing product-liability directive 85/374 as an example of a directive with an option, where the member states are allowed to recognize, or not, the “development-risk defense” in addition to directive 94/33 on the protection of young people at work); Vos, supra note 17, at 148 (noting, as well, directive 94/33 on the protection of young people at work as another example of such a directive).Google Scholar

19 See Vos, supra note 17, at 149 (referring to Council Directive 92/81/EEC as an example).Google Scholar

20 Id. at 150.Google Scholar

21 Directive 95/46, of the European Parliament and of the Council of 24 Oct. 1995 on the Protection of Individuals With Regard to the Processing of Personal Data and on the Free Movement of Such Data, 1995 O.J. (L 281) 31 can be quoted as an example of this form of differentiation. See Stephen A. Oxman, Exemptions to the European Union Personal Data Privacy Directive: Will They Swallow the Directive?, 24 B.C. Int'l & Comp. L. Rev. 191, 191 (2000), available at http://www.bc.edu/dam/files/schools/law/lawreviews/journals/bciclr/24_1/07_FMS.htm (noting a concern that the aforementioned directive might be already too flexible: allowing for too many exemptions); Gráinne de Búrca, Legal Principles as an Instrument of Differentiation? The Principles of Proportionality and Subsidiarity, in The Many Faces of Differentiation in EU Law 131, 142 (Bruno De Witte, Dominik Hanf & Ellen Vos eds., 2001).Google Scholar

22 Senden, Linda, Soft law in European Community Law (2004); Linda Senden & Sacha Prechal, Differentiation in and Through Community Soft Law, in The Many Faces of Differentiation in EU Law 181, 181 (Bruno De Witte, Dominik Hanf & Ellen Vos eds., 2001).Google Scholar

23 It is important to note that these are present not only in the existing EU Treaties, but also in the Accession Treaties. For example, they are in Council Directive 00/36, 2000 O.J. (L. 197) 19—the Maltese derogation—and the Polish declaration relating to abortion. See Chris Hilson, The Unpatriotism of the Economic Constitution? Rights to Free Movement and Their Impact on National and European Identity, 14 Eur. L.J. 186, 193 (2008).Google Scholar

24 Tuytschaever, Filip, The Changing Conception of Differentiation in European Union Law (1998).Google Scholar

25 See Stubb, , supra note 11, at 285.Google Scholar

26 Id. Google Scholar

27 Id. Google Scholar

28 Consolidated Version of the Treaty on European Union, title IV, May 9, 2008, 2008 O.J. (C 115) 13, 27 [hereinafter Treaty on EU].Google Scholar

29 See Avbelj, , supra note 13, at 134–38 (providing the following historical overview).Google Scholar

30 Hanf, Dominik, Flexibility Clauses in the Founding Treaties, from Rome to Nice, in The Many Faces of Differentiation in EU Law 3, 7 (Bruno De Witte, Dominik Hanf & Ellen Vos eds., 2001).Google Scholar

31 Id. at 8. These, for example, included the Protocol on German Internal Trade, which absolved what was then Western Germany from instituting a required EU customs regime with Eastern Germany; Banana Protocol, Protocol on Luxembourg, etc. Id. Google Scholar

32 Ehlermann, Claus-Dieter, Differentiation, Flexibility, Closer Cooperation: The new Provisions of the Amsterdam Treaty (1998); Colino, supra note 10, at 4.Google Scholar

33 See Walker, , supra note 8, at 364; Colino, supra note 10, at 8 n.8 (referring to Nomden 1998).Google Scholar

34 Colino, , supra note 10, at 4.Google Scholar

35 Single European Act, Feb. 17, 1986, 1987 O.J. (L 169) 1 [hereinafter SEA]. The SEA came into force in July 1987. Id. Google Scholar

36 Countries, European Union, http://europa.eu/about-eu/countries/index_en.htm (last visited Jan. 4, 2013) (noting that Greece joined the European Union in 1981, whereas Spain and Portugal followed five years later in 1986).Google Scholar

37 See Hanf, , supra note 30, at 10–11.Google Scholar

38 EC Treaty art. 130t (as in effect 2002) (now TFEU art. 150).Google Scholar

39 See Hanf, , supra note 30, at 10.Google Scholar

40 The Maastricht Treaty, Feb. 7, 1992, 1992 O.J. (C 191) 1 [hereinafter ToM].Google Scholar

41 Harmsen, Robert, A European Union of Variable Geometry: Problems and Perspectives, 45 N. Ir. Legal Q. 109, 110 (1994).Google Scholar

42 See Hanf, , supra note 30, at 16–18. The most notorious were the protocols on the acquisition of second homes in Denmark and the Irish abortion protocol. Id. Google Scholar

43 ToM, Protocol on Social Policy, 1992 O.J. (C 191) 1, 90 (stating, for example, that the United Kingdom is not participating).Google Scholar

44 Schäuble, Wolfgang & Lamers, Karl, Reflections on European Policy, in Building European Union: A Documentary History and Analysis 255 (Trevor Salmon & Sir William Nicolle eds., 1997). Compare Ehlermann, supra note 32 (noting that academics differ as to whether their proposal was an example of variable geometry); with Walker, supra note 8 (noting that their proposal was an example of concentric circles).Google Scholar

45 Gillespie, Paul, The Promise and Practice of Flexibility, in Amsterdam: What the Treaty Means ch. 3 (Ben Tonra ed., 1997).Google Scholar

46 Wall, Sir Stephen et al., Flexibility and the Future of the European Union, A Federal Trust Report On Flexible Integration in the European Union 9 (Oct. 2005), available at http://mayapur.securesites.net/fedtrust/filepool/FedT_Flexibility_report.pdf.Google Scholar

47 Ehlermann, , supra note 32, at 250.Google Scholar

48 Hanf, , supra note 30, at n.88.Google Scholar

49 Weizsäcker, Richard von, Jean-Luc Dehaene & David Simon, The Institutional Implications of Enlargement, Report to the European Commission (Oct. 18, 1999), available at http://www.esi2.us.es/~mbilbao/pdffiles/repigc99.pdf. The previously referenced report is also known as the Wise Men or Dehaene report. European Union: Wise Men Recommend that Commission Table Draft Treaty, EuroPolitics, Oct. 20, 1999, available at http://www.europolitics.info/european-union-wise-men-recommend-that-commission-table-draft-treaty-artr150332-32.html.Google Scholar

50 Fischer, Joschka, Vice Chancellor and Foreign Minister, Germany, Quo vadis Europa?, Address at Humboldt University (May 12, 2000).Google Scholar

51 Chirac, Jacques, President, France, Our Europe, Address Before the German Bundestag (June 27, 2000).Google Scholar

52 Blair, Tony, Prime Minister, Great Britain and Northern Ireland, Europe's Political Future, Address to the Polish Stock Exchange, Warsaw (Oct. 6, 2000).Google Scholar

53 Treaty of Nice Amending the Treaty on European Union, The Treaties Establishing the European Communities and Certain Related Acts, Mar. 10, 2001, arts. 11 & 11(a), 2001 O.J. (C 80) 1, 13–14, 36–37 [hereinafter the Treaty of Nice].Google Scholar

54 Treaty of Lisbon Amending the Treaty on European Union and the Treaty Establishing the European Communities, Dec. 13, 2007, Protocol on the Application of the Charter of Fundamental Rights of the European Union to Poland and to the United Kingdom, 2007 O.J. (C 306) 1, 156 [hereinafter Treaty of Lisbon]; see also Julio Baquero Cruz, What's Left of the Charter? Reflections on Law and Political Mythology, 15 Maastricht J. Eur. & Comp. L. 65 (2008).Google Scholar

55 Mahony, Honor, EU Treaty Negotiations Proceed Slowly, EuObserver.com, Sept. 19, 2007, http://euobserver.com/institutional/24783; Michael Dougan, The Treaty of Lisbon 2007: Winning Minds, Not Hearts, 45 Common Mkt. L. Rev. 617, 680–87 (2008) (noting that the UK, in the Area of Freedom Security and Justice, in particular police and judicial cooperation in criminal matters, but also in the Schengen acquis, reserved itself the right to opt-out of rules already binding on it).Google Scholar

56 There were two ultimately unsuccessful attempts to implement the enhanced cooperation: One in 1999 at the Cologne European Council aimed at overcoming Spain's opposition to the European Company Statute, and another in 2001 targeting the Italian reluctance to support the framework decision on the European Arrest Warrant. See José M. de Areilza, The Reform of Enhanced Co-operation Rules: Towards Less Flexibility?, in The Many Faces of Differentiation in EU Law 27, 33 (Bruno De Witte, Dominik Hanf & Ellen Vos eds., 2001); Daniel Thym, “United in Diversity”—The Integration of Enhanced Cooperation into the European Constitutional Order, 6 German L.J. 1731, 1737 (2005).Google Scholar

57 Council Decision 210/405, 2010 O.J. (L 189) 12 (EU), available at http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:189:0012:0013:EN:PDF.Google Scholar

58 Commission Proposal for a Council Regulation Implementing Enhanced Cooperation in the Area of the Creation of Unitary Patent Protection with Regard to the Applicable Translation Arrangements, COM (2011) 216 final (Apr. 13, 2011).Google Scholar

59 Treaty on European Union art. 20.1, July 29, 1992, 1992 O.J. (C 191) 1, 83 [hereinafter TEU].Google Scholar

60 TFEU art. 327.Google Scholar

61 TFEU art. 326.Google Scholar

62 TFEU art. 326.Google Scholar

63 See Piris, , supra note 4, at 121.Google Scholar

64 Tully, James, Strange Multiplicity: Constitutionalism in an Age of Diversity ch. 3 (1995).Google Scholar

65 See Walker, , supra note 8, at 382.Google Scholar

66 See Avbelj, , supra note 13, at 139–40.Google Scholar

67 See id. at 142.Google Scholar

68 See Hildebrandt, & Wefing, , supra note 2.Google Scholar

69 See José Manuel Durão Barroso, President of the European Commission, State of the Union 2012 Address, Address to the Plenary Session of the European Parliament (Sept. 12, 2012), available at http://europa.eu/rapid/press-release_SPEECH-12-596_en.htm (stating, in a somewhat dramatic way: “To me, it is this reality that is not realistic. This reality cannot go on.”).Google Scholar

70 Treaty on Stability, Coordination and Governance in the Economic and Monetary Union, Jan. 1, 2013, available at http://www.european-council.europa.eu/media/639235/st00tscg26_en12.pdf [hereinafter the Fiscal Compact].Google Scholar

71 See Balzacq, Thierry et al., Security and the Two-Level Game: The Treaty of Prüm, the EU and the Management of Threats 1 (Ctr. for Eur. Policy Studies, Working Document No. 234, 2006) (noting that on 27 May 2005, seven EU Member States—“Belgium, Germany, Spain, France, Luxembourg, the Netherlands and Austria”—signed the Treaty of Prüm to establish the “highest possible standard of cooperation … [for] combating terrorism, cross-border crime and illegal migration” as well as several informal groups to combat terrorism, organized crime, and drug abuse such as the TREVI and Pompidou group).Google Scholar

72 See the Fiscal Compact art. 16:Google Scholar

73 See About the Eurogroup, The Eurogroup, Eurozone Portal, http://eurozone.europa.eu/eurogroup/about-the-eurogroup?lang=en (“Eurogroup meetings are attended by the Eurogroup President, the Finance Minister of each Member State of the euro area, the Commissioner for economic and monetary affairs, and the President of the European Central Bank.”). Additionally “[t]he Chairman of the Economic and Financial Committee's Eurogroup Working Group also attends, to present the preparatory work done in that Group.” Id. Google Scholar

74 See European Council Conclusions, Brussels European Council 13 (Apr. 20, 2011), available at http://www.consilium.europa.eu/uedocs/cms_data/docs/pressdata/en/ec/120296.pdf (including The Euro Plus Pact which applies to “the euro area Heads of State or government and … Bulgaria, Denmark, Latvia, Lithuania, Poland, Romania. …”).Google Scholar

75 Most notably, the Mediterranean Union.Google Scholar

76 See Cameron Comes Under Fire for ‘Phantom Veto', EurActiv.com, Feb. 1, 2012, http://www.euractiv.com/uk-europe/cameron-comes-fire-phantom-veto-news-510498; In Quotes: Timeline of Reaction to UK's EU Treaty veto, BBC News, Dec. 13, 2011, http://www.bbc.co.uk/news/uk-politics-16137256.Google Scholar

77 See Rettman, Andrew, Poland Renews Attack on Eurozone-only Summits, EUObserver.com (Jan. 19, 2012), http://euobserver.com/19/114945.Google Scholar

78 See Paris, Berlin Hasten Plans for ‘two-speed Europe', EurActiv.com (Nov. 28, 2011), http://www.euractiv.com/euro-finance/paris-berlin-hasten-plans-speed-europe-news-509243; The Future of the EU: Two-speed Europe, or Two Europes?, The Economist (Nov. 10, 2011), available at http://www.economist.com/blogs/charlemagne/2011/11/future-eu; Quentin Peel, Germany and Europe: A very Federal Formula, Financial Times (Feb. 9, 2012), available at: http://www.ft.com/intl/cms/s/0/31519b4a-5307-11e1-950d-00144feabdc0.html#axzz1uM74FfD8.Google Scholar

79 Sepos, Angelos, Differentiated Integration in the EU: The Position of Small Member States 2 (Eur. Univ. Inst. Robert Schuman Ctr. for Advanced Stud., Working Paper No. 2005/17, 2005), available at http://www.eui.eu/RSCAS/WP-Texts/05_17.pdf.Google Scholar

80 Pescatore, Pierre, International law and Community law—a Comparative Analysis, 7 Common Mkt. L. Rev. 167, 181 (1970); José M. de Areilza, Enhanced Cooperation in the Treaty of Amsterdam: Some Critical Remarks 2 (Harvard Jean Monnet Working Paper No. 13/98, 1998) (characterizing flexibility as a statal grab for power).Google Scholar

81 See Haas, Ernst B., The Obsolescence of Regional Integration Theory (1975) (Univ. of California, Berkeley Inst. of Int'l Studies Ser. No. 25, 1975).Google Scholar

82 Allegedly defined as an ever closer union between the peoples of Europe, whose nature it is that it should proceed only one way. See Deirdre Curtin, The Constitutional Structure of the Union: A Europe of Bits and Pieces, 30 Common Mkt. L. Rev. 17 (1993). For an even more radical view, see Pierre Pescatore, Aspects Judiciaires de l'Acquis Communautaire, 17 Rev. Trimestrielle de Droit Eur. 617, 623 (1981) (arguing that the European Community is inherently bound to progress, presumably to more integration, and that the way back is inconceivable).Google Scholar

83 Maduro, Miguel Poiares, How Constitutional Can the European Union Be? The Tension Between Intergovernamentalism and Constitutionalism in the European Union (Jean Monnet Working Paper No. 5/04, 2004), available at centers.law.nyu.edu/jeanmonnet/archive/papers/04/040501-18.rtf.Google Scholar

84 See Avbelj, , supra note 13, at 149.Google Scholar

85 Id. at 144–45.Google Scholar

86 Tuytschaever, Filip, EMU and the Catch-22 of EU Constitution-Making, in Constitutional Change in the EU: From Uniformity to Flexibility 173, 195 (Gráinne De Búrca & Joanne Scott eds., 2000).Google Scholar

87 See Piris supra note 4, at 143–48.Google Scholar