¹ Case 6/64, Costa v. E.N.E.L., 1964 E.C.R. 1251.Google Scholar

² Treaty Establishing a Constitution for Europe, Dec. 16, 2004, 2004 O.J. (C310) 53 [hereinafter CT].Google Scholar

³ E.g. Treaty on European Union, 1992 O.J. (C191) 1 [hereinafter TEU], art. 95(4)-(10), CT art. III-172(4)-(10), and CT art. 176, Treaty Establishing the European Community, Nov. 10, 1997, 1997 O.J. (C 340) 3 [hererinafter EC Treaty], art. III-234(6).Google Scholar

⁴ One “minor” example: the Protocol on the Acquisition of Property in Denmark of 1992 which continues to be attached to the Constitution.Google Scholar

⁵ For various forms of “actual and potential”, “inter-state and intra-state”, “temporary and non-temporary”, “general and specific” as well as “positive and negative discrimination” in primary and secondary European law see the extensive analysis by Filip Tuytschaever, Differentiation in European Union Law (1999) and Dominik Hanf, Differentiation in the Law of European Integration (2002).Google Scholar

⁶ Gráinne de Búrca, Differentiation within the ‘Core'?, in Constitutional Change in the EU 133, 133 (Gráinne de Búrca & Joanne Scott eds., 2000).Google Scholar

⁷ On sector-specific forms of horizontal differentiation, see Bast in this volume.Google Scholar

⁸ See, for example, Treaty of Accession art. 24, Sep. 23, 2003, 2003 O.J. (C 227) E. on the possible suspension of the free movement of workers for a period of up to seven years after the 2004 enlargement Art. 24 of the Act of Accession in combination with the respective Annexes.Google Scholar

⁹ CT Protocol No. 13, art. 9: “The UK may notify the Council at any time of its intention to adopt the euro.” Similarly for Denmark Protocol No. 14.Google Scholar

¹⁰ See Daniel Thym, Ungleichzeitigkeit und Europäisches Verfassungsrecht 79-130 (2004); available at http://www.thym.de/daniel/ungleichzeitigkeit. The special status of the UK and Denmark is continued with slight modifications in Protocols Nos 17, 19 and 20 attached to the CT.Google Scholar

¹¹ This article follows the spelling of the Treaty of Nice and the constitutional Treaty which speaks of “cooperation” and does not use the British-English “co-operation”.Google Scholar

¹² The general mechanism for enhanced cooperation comprises specific rules for CFSP in Art. III-419(2) and 420(2) CT and is complimented by various forms of “asymmetric” defense cooperation in CT art. I-41, art III-310-312. A preliminary assessment is given by Matthias Jopp & Elfried Regelsberger, GASP und ESVP im Verfassungsvertrag, 26 Integratioqn 550, 552 (2003); Christian Deubner, Verstärkte Zusammenarbeit in der verfassten Europäischen Union, 27 Integration 274, 282 (2004) and Thym, supra note 10, at 162, 173.Google Scholar

¹³ Constantinesco, Vlad, Les clauses de coopération renforcée, 33 Revue trimesterielle de droit europeen 751, 752 (1997) (quoting Renaud Dehousse).Google Scholar

¹⁴ Guy Verhofstadt, Belgian prime minister, Speech to the European Policy Centre: A Vision for Europe (Sep. 21, 2000) (A few weeks before the Nice IGC), available at: http://www.europa.eu.int/futurum.Google Scholar

¹⁵ Curtin, Deirdre, The Constitutional Structure of the Union: A Europe of Bits and Pieces, 30 Common Market Law Review 17, 67 (1993), albeit not with regard to enhanced cooperation.Google Scholar

¹⁶ Weatherhill, Stephen, 'If I'd Wanted You to Understand I Would Have Explained It Better', in Legal Issues of the Amsterdam Treaty 21, 22 (David O'Keeffe & Patrick Twomey eds., 1999).Google Scholar

¹⁷ Constantinesco, , supra note 13, at 758.Google Scholar

¹⁸ Indeed, former internal market Commissioner Frits Bolkestein supported the idea of harmonizing corporate taxation asymmetrically; see Leader: Strange Bedfellows, Financial Times, July 20, 2004.Google Scholar

¹⁹ CT art. I-44(2); TEU art. 44a.Google Scholar

²⁰ CT art. I-44(1); TEU art. 43(a).Google Scholar

²¹ CT art. III-416, “Any enhanced cooperation shall comply with the Constitution and the law of the Union”; more explicitly TEU art. 43(c): “respect the acquis communautaire.”Google Scholar

²² CT art. I-44(4); TEU art. 44(2).Google Scholar

²³ Such as the British opt-out from Maastricht's Agreement on Social Policy criticized for “social dumping” among others by Gisbert Brinkmann, Lawmaking under the Social Chapter of Maastricht, in Lawmaking in the European Union 239, 261 (Paul Craig & Carol Harlow eds., 1998).Google Scholar

²⁴ See, supra notes 3-8 (and accompanying text within this piece).Google Scholar

²⁵ On the latter aspect, infra section C.II.Google Scholar

²⁶ Bogdandy, Armin von, Europäische Prinzipienlehre, in Europäisches Verfassungsrecht 149, 180 (Armin von Bogdandy ed., 2003). For further explanations of asymmetry as an expression of the gradual transition of European integration from the functionalist integration logic of the single market to political union see Thym, supra note 10, at 342-8.Google Scholar

²⁷ See art. 1 Schengen Protocol (= Protocol No. 17 attached to the CT).Google Scholar

²⁸ See Chairman of the EP-Committee on Justice and Home Affairs Graham Watson, Go Ahead on Arrest Warrant Without Italy, Financial Times, Dec. 8, 2001. The debate on the asymmetric introduction of carbon dioxide taxes never got off the ground; Europas Umweltschützer fordern 'Öko-Schengen', Frankfurter Allgemeine Zeitung, Aug. 15, 2000. On corporate tax harmonization see Leader: Strange Bedfellows, supra note 18.Google Scholar

²⁹ See Gaja, Giorgio, How Flexible is Flexibility under the Amsterdam Treaty, 35 Common Market Law Review 855, 870 (1998) (a criticism of the Amsterdam and Nice regimes); Wolfgang Wessels, Die Vertragsreform von Nizza, 24 Integration 8, 15 (2001) and Jo Shaw, The Treaty of Nice: Legal and Constitutional Implications, 7 European Public Law 195, 202 (2001).Google Scholar

³⁰ The Amsterdam Treaty had originally required the participation of the majority of Member States, while the Treaty of Nice lowered the criterion to eight Member States in TEU art. 43(g), (8 are the majority of 15, but about one third of 25). The Constitution now returns to a relative threshold of one third in CT art. I-44(2).Google Scholar

³¹ CT art. I-44(1); TEU art. 43(a). The additional requirement of protecting the Union's interests and reinforcing the integration process does not constitute independent legal hurdles, since respect for them is arguably inherent in the Union's objectives and assessed during the complicated authorization procedure discussed below.Google Scholar

³² CT art. III-416(1); TEU art. 43(b) and (c).Google Scholar

³³ CT art. III-417 and TEU art. 43(h); the rather unclear Amsterdam obligation to respect the “interests” of the non-participating Member States had already been deleted by the Treaty of Nice. The remaining obligation stems logically from the limited geographic scope of asymmetric Union law.Google Scholar

³⁴ Explicitly TEU art. 43(d) and, without explicit reference to the principle of conferral, CT art. I-44(1). The deletion of the explicit reference to the principle of attributed powers does of course not entail that they are not bound by the principle of conferral under CT art. I-11(1), (EC Treaty art. 5(2)) as suggested by Janis A. Emmanoulidisj & Claus Giering, In Vielfalt geeint – Elemente der Differenzierung im Verfassungsentwurf, 26 Integration 454, 457 (2003).Google Scholar

³⁵ Elsewhere, I have given a more thorough analysis of this argument, including references to and discussion of possible alternative views. See Thym, supra note 10, at 68-9, 250-4.Google Scholar

³⁶ See, for instance, Case 240/83, Procureur de la République v. ADBHU, 1985 E.C.R. 539, para. 9.Google Scholar

³⁷ The transfer of structural funds such as the European Regional Development Fund (ERDF) into enhanced cooperation would have implied asymmetric financing in accordance with CT art. III-423, TEU art. 44a and would be in obvious conflict with the underlying principle of solidarity.Google Scholar

³⁸ The comment on the original proposal of a new art. J in The European Convention, CONV 723/03, (May14, 2003), at 20 simply states that the wording was taken from the Treaty of Nice.Google Scholar

³⁹ E.g. Hatje, Armin, Art. 11 EGV, in EU-Kommentar 11 (Jürgen Schwarze ed., 2000) (“entscheidend einschränkt”).Google Scholar

⁴⁰ Treaty of Amsterdam Amending the Treaty on European Union, the Treaties Establishing the European Communitites and Certain Related Acts, Oct. 2, 1997, 1997 O.J. (C 340) 1 art. 11(1)(e) and, similarly, Case 8/74, Procureur du Roi v. Benoît, 1974 E.C.R. 837, para. 7.Google Scholar

⁴¹ Three commentators work in different languages. See Helmut Kortenberg (pseudonym), Closer Cooperation in the Treaty of Amsterdam, 35 Common Market Law Review 833, 849 (1998); Rainer Hofmann, Wie viel Flexibilität für welches Europa, 34 Europarecht 713, 724 (1999); and Constantinesco, supra note 13, at 761.Google Scholar

⁴² I have developed this argument in more detail in Thym, supra note 10, at 69-72. There, I also show that the additional prohibition of distortions of competition in CT art. III-416, TEU art. 43(f) should be interpreted in line with EC competition law, i.e. the Commission is obliged to asses and explain possible distortions in its decision (not) to propose the authorization of enhanced cooperation under CT art. III-419(1), (EC Treaty art. 11(1)), while judicial review of these complex economic evaluations is largely confined to an examination of the underlying facts and the legal consequences the Commission deduces therefrom.Google Scholar

⁴³ Any Member State or institution may challenge the authorization to establish an enhanced cooperation (or the refusal of the Commission to present a proposal) in accordance with the general rules on access to the Court.Google Scholar

⁴⁴ CT art. III-419(1); EC Treaty art. 11(1); the specific procedure for criminal matters in Art. 40a EU is given up in the Constitution, but specificities continue in CFSP.Google Scholar

⁴⁵ Art. III-419(1) CT goes beyond TEU art. 45 and the Nice version of EC Treaty art. 11(2).Google Scholar

⁴⁶ The vote by qualified majority corresponds to EC Treaty art. 11(2) EC, while the Treaty of Nice's additional renvoi to the European Council without veto option has been abolished (under the Treaty of Amsterdam any Member State could veto the decision at this level). Only for CFSP unanimity is required under CT art. I-23(3), III-419(2). On the harmonization of criminal law see the specific rules in CT art. III-270(3), (4) and CT art. III-271(3), (4).Google Scholar

⁴⁷ Ehlermann, Claus Dieter, Differentiation, Flexibility, Closer Co-operation, 4 European Law Journal 246, 254 (1998).Google Scholar

⁴⁸ See Treaty Establishing a Constitution for Europe art. III-418(1) and art. III-420(1).Google Scholar

⁴⁹ Comment on European Convention, supra note 38, at 10, 22 explicitly refer to monetary union and the Schengen evaluation procedure under Art. 3(2) of the 2003 Act of Accession (which is no example of asymmetry, since the new Member States are – contrary to the UK and Ireland – members of the Schengen group, with the duration of the transition period depending on technical adaptations; see Thym, supra note 10, at 114-8).Google Scholar

⁵⁰ Opinion Case C-1/91, European Economic Area, 1991 E.C.R. I-6079, para 21.Google Scholar

⁵¹ Walter Hallstein, Der unvollendete Bundesstaat 33 (1969) (author's translation).Google Scholar

⁵² CT, Preamble Recital 3.Google Scholar

⁵³ See Bogdandy, von, supra note 26, 184-202, and Armin Hatje, Grenzen der Flexibilität einer erweiterten Europäischen Union, 40 Europarecht 148 (2005) (on the asymmetric accommodation of diversity and section B above and on the sequence of the principles of unity and diversity among Europe's “constitutional principles”).Google Scholar

⁵⁴ Curtin, , supra note 15, at 51-2 only debates whether the present EC TreatyArt. 10 may be invoked to oblige the UK to rejoin the advance group at some point at the future. Unfortunately, Anne Peters, Elemente einer Theorie der Verfassung Europas 449 (2001) extends this criticism to later forms of asymmetry such as enhanced cooperation without analyzing their difference in form and substance.Google Scholar

⁵⁵ Hans Kelsen, Allgemeine Staatslehre 165 (1925) (author's translation).Google Scholar

⁵⁶ Georg Jellinek, Staatslehre 642 (2^nd ed. 1905) (author's translation).Google Scholar

⁵⁷ See the overview Flexibility in Constitutions, (Annette Schrauwen ed., 2^nd ed. 2002).Google Scholar

⁵⁸ The maintenance of these characteristic principles of EU law stems from the deliberations above and is dealt with in Thym, supra note 10, at 233-268.Google Scholar

⁵⁹ See Witte, Bruno de, “Old Flexibility”, in Constitutional Change in the EU, supra note 6, at 31-58; Thym, supra note 10, at 181-202, 297-320, (on the cooperation of some Member States the important contribution).Google Scholar

⁶⁰ Which in casu are the ordinary legislative procedure (hitherto known as co-decision) for consumer protection (Treaty Establishing a Constitution for Europe art. I-34(1), III-235) a unanimous Council decision after consultation of the Parliament for tax harmonization (Treaty Establishing a Constitution for Europe art. III-171).Google Scholar

⁶¹ Treaty Establishing a Constitution for Europe art. III-416; the specific (and declaratory) obligation to respect “the relevant institutional provisions” of the Treaties in TEU art. 44(1) was not integrated in the constitutional Treaty.Google Scholar

⁶² As remarked incorrectly by Werner Schröder, Verfassungsrechtliche Beziehungen zwischen Europäischer Union und Europäischen Gemeinschaften, in von Bogdandy, supra note 26, at 413-4. Unfortunately, the wording of Treaty Establishing a Constitution for Europe Art. I-44(1), TEU art. 43 may be misunderstood in this respect when it refers to enhanced cooperation allowing some Member States to “make use” of the Union's institutions and procedures.Google Scholar

⁶³ Such as the classic British debate on the “West Lothian Question” concerning the voting rights of Scottish MPs in matters devolved to the Scottish Parliament (but decided in Westminster for England).Google Scholar

⁶⁴ CT Protocol No. 12 does not change its legal nature as an informal “talking shop” with decisions being taken in the regular Ecofin Council; Thym, supra note 10, at 143-9.Google Scholar

⁶⁵ CT art. I-44(3); TEU art. 44(1).Google Scholar

⁶⁶ CT art. III-422(2) was first proposed in the text submitted to the Convention for its last working session – one day before the text was solemnly adopted by consensus; The European Convention, CONV 847/03, (July 9, 2003). Its reference to Treaty Establishing a Constitution for Europe art. I-44(3) clearly indicates that the outs may not block the move towards qualified majority voting.Google Scholar