Greenland and European defense: when the EU clause can be triggered

In the event that the United States does not stop its aims on Greenland the European Union could respond militarily. Article 42 of the Treaty on European Union (TEU) provides in paragraph 7 that “if a Member State suffers armed aggression on its territory, the other Member States have the obligation to help and assist it with all the means at their disposal, in accordance with Article 51 of the United Nations Charter. This does not prejudice the specific character of the security and defense policy of certain Member States”.

It is, in practice, the “mutual defense clause“of the EU, often compared toArticle 5 of NATOalbeit with different scope and mechanisms. Since Greenland is a territory of Denmark, it could therefore make use of it.
The article does not automatically oblige the sending of troops, but leaves the choice of means up to the States. However, military assistance is explicitly foreseen as a possibility for common defense.

In the history of the European Union, article 42.7 it was invoked only once from France after the terrorist attacks in Paris of November 13, 2015 which caused 130 deaths and over 250 injuries. Although it was not an “invasion” in the strict sense, the mutual defense clause was still applied because the jihadist attack was considered “an armed aggression”.