NATO’s Article 5 collective-defense clause remains unlikely to be invoked before 2027, as traders see at 94 percent probability for “No,” because the Russia-Ukraine war has stayed confined to non-member territory despite repeated hybrid incidents along the eastern flank. NATO has responded with Article 4 consultations, forward deployments to Poland, the Baltics, and Romania, and increased air and missile defenses rather than collective-defense activation. Tensions tied to the 2026 NATO Summit and U.S. policy debates have not produced an armed attack on any ally that meets the threshold for invocation. Historical precedent shows Article 5 triggered only once, in 2001, reinforcing expectations that current deterrence and diplomatic channels will continue to manage risks through 2026.