NATO’s Article 5 collective-defense clause remains uninvoked since 2001, with recent hybrid incidents such as 2025 drone incursions over Poland and Estonian airspace violations prompting only Article 4 consultations and enhanced forward deployments rather than alliance-wide activation. Ongoing Russia-Ukraine tensions, Baltic flank pressures, and early 2026 U.S. policy frictions over Greenland have been addressed through diplomacy, air policing, and infrastructure investments instead of triggering the high consensus threshold for an armed-attack determination. As of late May 2026, NATO parliamentary discussions continue to emphasize deterrence measures and critical-infrastructure protection without any member seeking or securing the unanimous invocation required. Traders therefore assign a 90% probability to no invocation before the end of 2026, reflecting the alliance’s consistent preference for sub-threshold responses that preserve flexibility.