Improving the EU’s Readiness to Admit Ukraine Without Amending the Lisbon Treaty

Abstract

In the unprecedented circumstances of the full-scale war in Ukraine, the country’s accession to the European Union (EU) has come to be viewed as a geopolitical imperative. However, despite renewed political commitment to enlargement, the Union remains poorly equipped to admit new members without jeopardising its internal cohesion and functionality. This article examines how the EU can enhance its institutional readiness to integrate Ukraine without amending the Lisbon Treaty. It identifi es four complementary reforms that can strengthen the Union’s decisionmaking and enforcement capacities: (a) broader use of Qualifi ed Majority Voting (QMV); (b) activation of the passerelle clauses as a legal bridge toward fl exibility; (c) strategic use of constructive abstention to preserve unity in the Common Foreign and Security Policy (CFSP); and (d) development of a cooperative enforcement model to improve implementation of EU legislation. By linking these mechanisms to the current debate on enlargement and governance, the article demonstrates that meaningful institutional adjustment is possible within the existing Treaty framework. It argues that such reforms would not only prepare the EU for Ukraine’s accession but also strengthen the Union’s overall legal coherence, external credibility, and rule-of-law resilience. To conclude, this paper advocates that the momentum created by Ukraine’s membership application should be seized upon to build a more responsive, credible, and strategically autonomous Union – one capable of deepening its integration while widening its membership.