NATO has invoked Article 5 only once in its history, after the 9/11 attacks, and recent incidents such as Russian drone incursions into Polish airspace, airspace violations near Estonia, and a March 2026 missile incident over Turkey have prompted only Article 4 consultations rather than collective defense measures. The Russia-Ukraine conflict continues with NATO allies providing weapons and training through mechanisms like the Prioritized Ukraine Requirements List, yet without direct alliance troops on Ukrainian soil that could provoke escalation. U.S. policy under the current administration has emphasized European burden-sharing and diplomatic talks toward a potential ceasefire, while hybrid threats remain below the armed-attack threshold required for invocation. These patterns sustain trader consensus that no qualifying trigger will occur before 2027.