NATO’s Article 5 collective defense clause requires unanimous allied agreement that an armed attack has struck member territory, a threshold met only once since 1949 after the September 11 attacks. Recent hybrid incidents, including September 2025 Russian drone incursions into Poland and airspace violations over Estonia, prompted Article 4 consultations and enhanced forward deployments such as Operation Eastern Sentry rather than invocation. In March 2026, NATO Secretary General Mark Rutte explicitly stated there was no discussion of triggering the clause following an Iranian missile incident near Turkey. Ongoing Russia-Ukraine fighting and isolated strikes on non-NATO soil have produced calibrated alliance responses focused on deterrence and eastern-flank reinforcement, sustaining trader consensus that no qualifying event will occur before the end of 2026.