Just like NATO, the European Union has its own mutual defence clause.
Yet Sweden and Finland's decision to join the transatlantic alliance in the wake of Russia's war in Ukraine appears to show that trust in the bloc's version is flimsy.
The EU's Mutual Defence Clause — Article 42.7 in the Treaty of Lisbon — was approved in 2007 and has been in force since 2009.
It states that "if an EU country is the victim of armed aggression on its territory, the other EU countries have an obligation to aid and assist it by all means in their power."
It came 60 years after the creation of NATO and its collective defence clause — Article 5 — which provides that "an attack against one Ally is considered as an attack against all Allies".
Both have been triggered only once in reaction to terrorist attacks — 9/11 for NATO and the November 13, 2015 attacks in Paris in the case of Article 42.7.
"On the face of it, they look very similar," Aylin Matlé, research fellow in the Security and Defence Programme at the German Council on Foreign Relations think tank, told Euronews. "But in fact, the wording of Article 42.7 is much stronger in my opinion in comparison to NATO's Article 5."
The reason is the word "obligation" which implies that other EU member states must provide assistance of some sort. Yet, "that doesn't mean that anything has to follow, that military action has to follow automatically," Matlé pointed out.
Article 42.7 stipulates that while the obligation of mutual defence is binding on all EU countries, "it does not affect the neutrality of certain EU countries and is consistent with the commitments of EU countries which are NATO members."
This means that the type of assistance provided, if any, is still up to the political leadership in
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