EU defense: big dreams, tight boundaries

Big discussions on EU defense have been ongoing for a long time, with renewed focus during the confirmation hearing of Andrius Kubilius, the newly appointed EU Commissioner for Defense from Lithuania. As the EU navigates its evolving role in defense, it's crucial to delineate what the Union can and cannot legally undertake in this domain. The EU’s ambition is evident, but the reality of its defense powers remains a careful balancing act, grounded in the Treaty on European Union (TEU).

The European Union's role in defense: an analytical overview

The EU’s involvement in defense is heavily guided and limited by its founding treaties, notably the Treaty on European Union (TEU). These treaties affirm that Member States retain sovereignty over defense, positioning the EU as a facilitator rather than a direct actor. However, the EU has increasingly used its powers in research, funding, and industrial policy to support defense initiatives, pushing the boundaries of its legal mandate.

1. Treaty on European Union (TEU) and defense limitations

The Common Security and Defence Policy (CSDP), defined in Article 42 TEU, incorporates defense into the EU’s Common Foreign and Security Policy (CFSP). This framework coordinates Member States’ defense efforts while keeping national sovereignty at the core.

• Article 42(2) specifies that while the CSDP includes “the progressive framing of a common EU defense policy,” any move towards a common defense requires unanimous consent from the European Council. This provision underscores that EU defense integration is conditional and that Member States hold ultimate authority over defense policy.
• Article 42(7) TEU, the mutual defense clause, commits Member States to assist a fellow Member if attacked. Yet, the clause stipulates that NATO commitments take precedence, positioning the EU's mutual defense obligation as secondary. This dual structure respects NATO's primary defense role and reinforces the EU's complementary stance rather than an autonomous military actor.
• Article 43 TEU further delineates the CSDP’s scope, authorizing humanitarian, peacekeeping, and crisis management missions but notably excluding large-scale offensive military operations. This highlights the EU's focus on security and stabilization, steering clear of traditional military interventions.

2. European Commission’s expanding role

While the European Commission has no mandate to command or organize defense operations, it has strategically expanded its influence via defense-related research and industrial initiatives.

• The European Defence Fund (EDF), established to finance collaborative defense projects, exemplifies the EU’s indirect support for defense. By focusing on funding defense technology, the EDF bolsters EU capabilities without direct military action, staying within treaty limits.
• The European Union Agency for the Space Programme (EUSPA) oversees civilian space projects like Galileo and Copernicus, which have dual-use potential for defense applications. EUSPA’s focus contrasts with the European Space Agency (ESA)—an intergovernmental body outside the EU framework—that collaborates on both civilian and military projects independently of EU oversight. ESA’s autonomy ensures its projects can support European defense broadly, while EUSPA operates strictly within EU regulations.

3. European Defence Agency (EDA)

The European Defence Agency (EDA) plays an essential support and implementation role across all major EU defense initiatives, bolstering Member States’ defense capabilities within treaty limits. Established under Article 45 TEU, the EDA coordinates key EU programs to foster Member State collaboration in defense.

EDA’s primary tools include:

• Capability Development Plan (CDP), identifying priority areas for defense investment,
• Coordinated Annual Review on Defence (CARD), which reviews and aligns Member States’ defense capabilities,
• Permanent Structured Cooperation (PESCO), fostering collaboration among willing Member States on specific defense projects, and
• EDF, which funds research and innovation across the EU defense sector.

By managing these tools, the EDA helps elevate the EU’s defense ambitions without infringing on national sovereignty.

4. Permanent Structured Cooperation (PESCO)

Article 46 TEU introduced Permanent Structured Cooperation (PESCO), a framework allowing willing Member States to deepen their defense collaboration without obligating full EU participation. PESCO initiatives address specific areas such as capability development and interoperability, enabling a subset of EU nations to advance defense cooperation while avoiding mandatory integration.

PESCO illustrates the EU’s role as a defense enabler, respecting treaty limits by delegating major defense decisions to participating states and thus preserving national sovereignty.

5. Boundaries and limitations on EU action in defense

The current EU treaties sharply restrict direct action in defense. The EU’s involvement is limited to:

• Facilitating and coordinating within CFSP and CSDP frameworks,
• Funding research and development via the EDF,
• Supporting Member States’ collaborations (e.g., PESCO) without imposing EU-wide obligations, and
• Developing dual-use technologies that support both civilian and military objectives without direct engagement in military actions.

These provisions ensure that the EU’s role remains supportive rather than principal. While the European Commission has expanded its influence in defense-industrial and research areas, it operates within the legal boundaries established by the treaties. Some may view these activities as an indirect path toward greater EU influence in defense; however, Articles 42 to 46 TEU consistently reaffirm that sovereignty in defense policy lies with Member States.

EU defense role is important, but conclusively complimentary

The EU’s defense role, as defined by the TEU, is shaped around support, coordination, and funding—distinctly avoiding direct military engagement. Articles 42 and 43 TEU set clear limits, placing the primary authority over defense in the hands of Member States. Consequently, the EU’s initiatives, such as EDF and PESCO, represent an incremental expansion of influence but remain anchored in supportive rather than commanding capacities.

In parallel, the lack of a clear popular mandate on defense issues highlights that defense remains an area of national competence rather than an EU-wide responsibility. Furthermore, NATO’s primacy in European defense underscores this distinction; EU defense efforts, while ambitious, are ultimately secondary and supportive of the alliance’s established security structure. This layered approach reflects the EU’s legal constraints: high ambitions, carefully managed within the bounds of national sovereignty and existing defense alliances.