Autonomy, security, and enlargement: the CJEU’s case law under geopolitical pressure

Russia’s full-scale invasion of Ukraine has recalibrated the rationale of EU enlargement, shifting it from a predominantly technocratic exercise to a central component of the Union’s security architecture under Article 49 TEU. As noted in the enlargement literature (McAuliffe, 2008; Kaeding, Pollak & Schmidt, 2023), accession operates within a delicate balance between political discretion, constitutional constraint, and administrative capacity. The rapid decisions to grant candidate status to Ukraine and Moldova have intensified this tension, exposing the challenge of reconciling geopolitical urgency with the values enshrined in Article 2 TEU and the acquis on judicial independence and effective judicial protection. While parts of the Western Balkans continue to display resistance to rule-of-law reforms, Ukraine faces distinct structural constraints linked to judicial capacity and wartime governance (Haletska & Savchuk, 2023; Csaky, 2024). This paper argues that, despite its formal absence from accession negotiations, the Court of Justice of the European Union exerts an increasingly significant constitutional influence on the pre-accession process. Through its jurisprudence on the autonomy of EU law and Article 19(1) TEU, the Court has progressively elaborated a set of constitutional essentials that function as non-derogable limits on political discretion – an evolution consistent with analyses of its integrative and constitutionalising role (Lenaerts, 2017; Rosas, 2019). Building on the Conditionality Regulation judgments (Hungary v Parliament and Council, C-156/21; Poland v Parliament and Council, C-157/21) and the broader case law addressing systemic deficiencies in judicial independence, the paper shows how the CJEU has consolidated the rule of law as a structural condition of Union membership (reflecting concerns documented by Pech & Kochenov, 2021). The paper advances two main claims. First, the Court’s case law can be understood as a form of judicial European protection, in which safeguarding the coherence and primacy of EU law becomes integral to protecting the Union’s constitutional and security order. Second, the CJEU’s jurisprudence operates as a counter-contestation mechanism in candidate countries: it generates anticipatory compliance, strengthens pro-reform judicial actors, and shapes domestic constitutional dynamics even before accession – an effect consistent with recent analyses of judicial empowerment in enlargement contexts (Ognjanoska, 2021). The paper ultimately examines how these judicial constraints interact with the more pragmatic, security-driven approaches pursued by the Commission and the Council, and assesses whether the Court’s evolving case law constrains, enables, or subtly reshapes the EU’s geopolitical enlargement agenda.