NATO has invoked Article 5 only once in its history, following the 2001 attacks on the United States, with no subsequent triggers amid ongoing conflicts. Recent developments include Russian drone incursions into Polish airspace that prompted Article 4 consultations rather than collective defense obligations, alongside NATO's sustained support for Ukraine without direct member-state attacks. Alliance members have focused on raising defense spending targets, conducting enhanced exercises, and maintaining deterrence on the eastern flank, reducing escalation risks. U.S. policy shifts emphasizing European burden-sharing have not altered the core security guarantee or produced imminent threats. These factors underpin trader consensus that an armed attack sufficient to invoke Article 5 remains unlikely through 2026.