Reports of sabotage operations in Europe by Russia have further inflamed tensions on the continent (AP, Guardian, Politico). Article 4 of the North Atlantic Treaty, which created NATO, states that any member can call for consultations when they believe they are under threat, while Article 5 covers collective defense in the event of an armed attack against a member (NATO - Article 4, NATO - Article 5). Article 4 was last invoked in February 2022 by several NATO member states in response to Russia's invasion of Ukraine (The Conversation).

Confused? Check our FAQ or ask us for help. To learn more about Good Judgment and Superforecasting, click here.

To learn more about how you can become a Superforecaster, see here. For other posts from our Insights blog, click here.

NOTE 10 September 2025: We are aware of reports that Poland held consultations under Article 4 regarding Russian ordinance breaching Polish airspace and falling on Polish territory. As there is no evidence that these incidents were "a putative act or acts of sabotage," the question will remain open.

NOTE 11 September 2025: The question asks if a NATO member invoke either Article 4 or Article 5 in response to a putative act or acts of sabotage, which should be read as "a putative act or [putative] acts of sabotage." The member state must invoke Article 4 or Article 5 in response to acts that the member state purports to be sabotage to close the question.