The European Union will run simulations of its mutual-assistance mechanism in case of attack, a clause in the bloc’s governing treaty that has become more relevant amid strains in Nato.
These exercises would mimic the decision-making process if a member state called on the rest of the EU for military backup, according to a senior EU official. The drills will take place among EU ambassadors in Brussels and then at a defence ministers’ meeting in May in Cyprus, the official said. The topic will also be discussed at next week’s informal leaders’ summit in Cyprus.
The effort highlights how Europe is responding to a breakdown in transatlantic ties following Donald Trump’s threats to pull out of Nato and his stated desire to acquire Greenland, which is a semi-autonomous part of Denmark.
The EU’s article 42.7 states that if a member state is the “victim of armed aggression on its territory,” other member states have “an obligation of aid and assistance by all means in their power.”
As such, it’s more strongly worded than Nato’s essential article 5, which states that an armed attack against a member commits members to take “such action as it deems necessary,” including, but not necessarily, armed force. The EU, however, lacks Nato’s military might and structures to back it up.
The EU clause has only been triggered once, by France following 2015’s terror attacks. In early 2026, EU Commission President Ursula von der Leyen called for the bloc to bring the clause to life.
Cyprus, which is not a member of Nato due to its long-standing conflict with Nato member Turkey, is particularly interested in seeing the EU’s mutual assistance clause strengthened after an Iranian drone struck a British military base on the island in early May.
Nato’s article 5 has been activated once, following the September 11 2001 terrorist attacks on the US.