European Union countries are rethinking how they would respond if one of them were attacked, and Kaja Kallas will brief EU leaders on Article 42.7 of the EU Treaty on Thursday. The clause requires member states to provide aid and assistance, by all the means in their power, if another EU country comes under attack.
That debate is moving from the abstract to the practical. On May 4, national ambassadors on the Political and Security Committee will hold a closed-door meeting and take part in a table-top exercise on invoking Article 42.7, with the scenario expected to test a hybrid attack involving two member states, one in the south and one in the east. EU defense ministers will run their own scenario later in May.
The weight of the issue comes from what is happening around Europe, not from the clause itself. Article 42.7 has been invoked only once, after France triggered it in 2015 following the terrorist attacks, and Cyprus did not invoke it last month after being hit by Iranian drones. Now officials are gaming out how to use the clause in a crisis while fears of a potential Russian attack rise and doubts about U.S. commitments under Donald Trump linger.
That makes the exercise politically delicate. Frontline countries are concerned that too much focus on Article 42.7 could affect NATO, and the EU is trying to downplay any signal that it is seeking to replace the alliance. Latvian Defense Minister Andris Sprūds said EU efforts to engage more in the defense and security of Europe are welcome, but added that Article 42.7 should be consistent with, but not in competition with NATO’s Article 5.
Estonia’s defense minister, Hanno Pevkur, was even more explicit. He called Article 5 the bedrock of collective security, described Article 42.7 as a vital expression of European solidarity, and said NATO’s Article 5 holds the layer of operational military readiness that ensures our defense. One diplomat said the simulation is unlikely to play out a full military emergency like a Russian attack, adding, “Our goal is to avoid crossing the line of a military attack.”
The result is a test not just of a treaty clause but of how far Europe wants to push its own defense identity without blurring the line with NATO. If the talks and exercises produce a clearer answer, they will also expose how much uncertainty still remains about who moves first, and how, when the next crisis hits.