NATO allies have experienced no armed attack on member territory meeting the Article 5 threshold since the clause’s sole prior invocation after 9/11, sustaining trader consensus on a low near-term probability. Russian hybrid operations—including airspace incursions, suspected sabotage, and recent drone strikes near the Polish border—have prompted Article 4 consultations rather than collective defense measures. U.S. and European intelligence assessments flag only a possible limited probe sometime between autumn 2026 and 2029, constrained by Moscow’s Ukraine commitments. NATO’s July 2026 Ankara summit reaffirmed an “ironclad” commitment to Article 5, and European members have increased eastern-flank deployments and defense spending. With months remaining before the December 31, 2026 resolution, the absence of a qualifying trigger underpins current market pricing.