Mutual defence clause: what the requirement to help out other member states means 

Find out more about the mutual defence clause in our infographic  

The mutual defence clause, requiring EU countries to help a member state under attack, was invoked for the first time by France in November in the wake of the terrorist attacks in Paris. In a resolution adopted on 21 January, MEPs said this cooperation should serve to strengthen European security and defence and also called for a stronger role for EU institutions. Check out our infographic and learn more about the legal basis and its implications.

The legal basis

The mutual defence clause was introduced in 2009 under Article 42 (7) of the Treaty of the European Union. It says that EU countries are obliged to assist a fellow member state that has become “a victim of armed aggression on its territory” and that this support should be consistent with potential NATO commitments.

No formal procedure has been set out and the article does not say that the assistance should be military in nature, so countries such as Austria, Finland, Ireland and Sweden that have a policy of neutrality, can still cooperate.

What form of assistance?

Since the request for assistance was made on 17 November 2015, France has been holding bilateral talks with member states to see what kind of aid is available. Some countries have expressed a willingness to join operations against terrorists in Syria and Iraq, others are ready to increase their presence on other international missions, thus allowing French troops to be transferred elsewhere.

The EU's role

The role of the EU is limited as the exact type of assistance required is being agreed directly between states. Nevertheless, it could help to facilitate and coordinate the process.

MEPs adopted a resolution on 21 January, saying that the activation of the clause is an “opportunity to establish the ground for a strong and sustainable European Defence Union”. They also invited the EU’s foreign policy chief to propose practical arrangements and guidelines with regard to the mutual defence clause that would make use of the potential of EU institutions to facilitate implementation.

The legal text 
  • If a member state is the victim of armed aggression on its territory, the other member states shall have towards it an obligation of aid and assistance by all the means in their power, in accordance with Article 51 of the United Nations Charter. This shall not prejudice the specific character of the security and defence policy of certain member states. 
  • Commitments and cooperation in this area shall be consistent with commitments under the North Atlantic Treaty Organisation, which, for those states which are members of it, remains the foundation of their collective defence and the forum for its implementation.