Conditional Integration: Third-Country Participation in European Defence Procurement

The structural shift in joint defence procurement in Europe is being driven by war on the continent, fiscal pressure, and capability shortages revealed by high‑intensity warfare. While EU frameworks such as PESCO, the European Defence Fund (EDF), and European Defence Agency (EDA) programs are designed to strengthen the European defence technological and industrial base, the role of non‑EU partners has become both unavoidable and strategically important. The question is no longer whether third countries can participate, but under what conditions and with which trade‑offs.

Legally, third‑country participation is already embedded (though tightly controlled) within EU defence instruments. PESCO allows non‑EU states to join individual projects if they provide “substantial added value,” share EU security objectives, and accept governance rules. Norway, the United States, Canada, and the United Kingdom have all been admitted to specific PESCO projects, most notably Military Mobility, where regulatory alignment and infrastructure access matter more than industrial protectionism. EDF rules are stricter: third‑country entities cannot directly receive funding and are subject to ownership and control restrictions, though subsidiaries established in the EU can participate with some limitations. The legal framework therefore supports targeted participation while safeguarding strategic technologies and intellectual property.

Strategically, third‑country involvement serves three main purposes. First is interoperability. European capability development cannot be divorced from NATO force structures, where the US, UK, Norway, Turkey, and Canada remain central actors. Joint procurement projects that exclude key operational partners risk producing technically compliant but operationally misaligned systems. This is particularly relevant in C4ISR, missile defence, and air and maritime enablers, where standards integration is as important as platform acquisition.

Second is industrial scalability and supply‑chain resilience. Europe’s defence industry remains fragmented, and since 2022 limits in manufacturing capacity, shortages of key components and materials, and slow expansion of production lines have demonstrated restricted surge capacity. Recent joint ammunition procurement schemes coordinated by the EDA illustrate the tension: political pressure favours “buy European,” but operational urgency pushes toward mixed sourcing.

Third is alliance cohesion. Structured openings for partners such as the UK create political bridges after Brexit, reducing duplication between EU and NATO planning. UK participation in selected projects aligns with its role as Europe’s leading military spender and nuclear power. By contrast, leaving Turkey outside European defence formats can weaken operational effectiveness, since it removes access to a sizable defence industrial base and a geostrategic location spanning the Black Sea, Middle East, and Eastern Mediterranean. At the same time, deeper inclusion is politically and legally sensitive, as cooperation may conflict with sanctions regimes, arms export controls, and rule‑of‑law conditionality applied by the EU and its Member States.

Military exercises present fewer legal barriers but similar strategic dilemmas. Non‑EU participation in EU‑led exercises and capability demonstrations is already common through NATO, ad hoc coalitions, and EDA frameworks, and helps test multinational formations and new technologies under realistic conditions. However, when exercises are tied to EU capability development pipelines, sensitivities increase. Questions arise over who controls and can reuse the operational and performance data produced, how sensitive technologies and system capabilities can be protected from unwanted disclosure, and which authority has the mandate to formally validate results and standards for EU procurement and planning.

In conclusion, joint procurement is evolving into an instrument of geopolitical alignment as much as a tool for efficiency. While opening programs to third countries enhances capability coherence, it comes at the cost of diluting industrial sovereignty over strategic assets. However, restricting access safeguards the European industrial base but may slow delivery, increase costs, and weaken interoperability. The resulting model of conditional integration allocates partner access on a project‑by‑project and technology‑by‑technology basis, regulated by security‑of‑supply and control clauses. The main takeaway of this analysis is clear: European defence initiatives are not excluding partners, but are increasingly becoming strategically and selectively open.

Author(s): Paula Gomila Marqués, Senior Researcher, Policy Adviser & Project Manager , SAHER Europe