NATO's Article 4 allows any member to call for consultations with allies if it believes its territorial integrity, political independence, or security to be threatened.
This market will resolve to "Yes" if any NATO member invokes Article 4 of the North Atlantic Treaty between September 25, and October 15, 2025, at 11:59 PM ET. Otherwise, it will resolve to "No".
Article 4 is considered invoked as soon as a member formally requests consultations with NATO allies under Article 4, regardless of whether the request is later revoked.
For example, Poland's recent request for consultations on September 10, 2025, or Estonia's request on September 24, 2025 would each qualify for a "Yes" resolution.
If a member state only expresses intent to or is considering invoking Article 4, that alone does not suffice for a "Yes" resolution.
The primary resolution source for this market will be official information from NATO; authoritative statements from the requesting member government may also be used.