TY - CHAP A1 - Martill, Benjamin A1 - Sus, Monika ED - Leruth, Benjamin ED - Gänzle, Stefan ED - Trondal, Jarle T1 - Growing Apart Together? Brexit and the Dynamics of Differentiated Disintegration in Security and Defense T2 - The Routledge Handbook of Differentiation in the European Union N2 - Brexit initially raised the prospect of new forms of external differentiation in the European Union (EU), should the United Kingdom continue to participate in a number of the Union’s policy areas. Security and defence was one area where agreement on the terms of UK participation was more likely, given the clear interests of both sides in the development of a close partnership in this area. But agreement has been so difficult to reach, and the final Brexit deal makes no mention of collaboration in foreign, security and defence policy. We argue that the key to understanding this puzzle lies in understanding the politics of differentiated disintegration, of which Brexit is the prime example, and the distinction between strategic and political interests. While strategic interests constitute a driver for external differentiation, the political interests arising from the withdrawal process make it difficult to reach an agreement. Divorcing strategic cooperation from the short-term politics of negotiations is the first step to overcoming the stalemate, and this chapter presents several ways this can be achieved. By perceiving Brexit as a case of differentiated disintegration, this chapter accounts for the significant constraints associated with external differentiation as a mode of integration in the EU. KW - Disintegration KW - Brexit KW - Defence KW - Differentiation Y1 - 2022 UR - https://www.routledge.com/The-Routledge-Handbook-of-Differentiation-in-the-European-Union/Leruth-Ganzle-Trondal/p/book/9780367149659 SN - 9780429054136 U6 - https://doi.org/10.4324/9780429054136-47 SP - 696 EP - 711 PB - Routledge CY - London ER - TY - JOUR A1 - Martill, Benjamin A1 - Sus, Monika T1 - With or Without EU: Differentiated Integration and the Politics of Post-Brexit EU-UK Security Collaboration JF - European Papers - A Journal on Law and Integration N2 - Research on differentiated integration has flourished in recent years, highlighting the political and efficiency gains to be had from selective participation and third country engagement in EU policy areas. Proposals for an EU-UK security and defence agreement represented a paradigmatic example of differentiated disintegration, for which both strategic and political prospects initially appeared positive, yet which ultimately foundered on the back of the EU’s reluctance to create new third country models and subsequent political upheaval in the UK. This Article asks why these proposals failed and what this can tell us about the politics of differentiated (dis)integration, focusing on the referendum to the recent Ukraine crisis, and drawing on several elite interviews conducted with policymakers in London and Brussels. It shows that while the strategic benefits of differentiation increased following the Brexit vote, the growing concern in Brussels for the precedent set by Brexit, the collapse of issue-specific dynamics into a singular concern for UK “cherry picking”, and the rightward shift in UK politics occasioned by the Brexit negotiations all undermined the prospects for a differentiated outcome in security and defence. The Ukraine crisis, while precipitating significant changes in many European states, had thus far failed to alter the new status quo locked in after Brexit. KW - Brexit KW - differentiated integration KW - Ukraine War KW - European security KW - EU-UK relations KW - United Kingdom Y1 - 2022 U6 - https://doi.org/10.15166/2499-8249/611 VL - 7 IS - 3 SP - 1287 EP - 1302 ER -