The Joint Expeditionary Force in the European Security System: Institutional Evolution and Prospects for Partnership with Ukraine

Abstract

This article examines the opportunities and limitations of the Joint Expeditionary Force (JEF) as a regional defense cooperation framework and assesses prospects for partnership with Ukraine. It uses a qualitative case study design and documentary analysis of official materials and research publications, covering 2014 to 1 September 2026. The theoretical framework combines defense minilateralism with an institutional approach. The findings indicate that the JEF’s evolution combines organizational continuity with changing political priorities and expanding activities. Its flexibility enables interested states to participate in specific activities, while effectiveness depends on national decisions, resources and coordination with NATO. Evidence from exercises and NORDIC WARDEN demonstrates multinational coordination but is insufficient to establish the JEF’s independent deterrent effect. The analysis traces the expansion of agreed arrangements for Ukraine’s involvement and distinguishes partnership intentions from verified implementation outcomes. It proposes cooperation priorities in maritime security, critical infrastructure protection, unmanned systems and staff training, alongside conditional scenarios for JEF development to 2030. The study contributes by linking institutional analysis of the JEF with an assessment of mechanisms for partnership with Ukraine. Its principal limitation is reliance on open sources and limited evidence of operational outcomes.