US extended deterrence commitments, reinforced through NATO nuclear sharing arrangements and trilateral consultations with Japan and South Korea, continue to anchor allied nonproliferation policies under the NPT. No NATO member or designated Major Non-NATO Ally has initiated or advanced a verified weapons program capable of producing deliverable warheads by the end of 2026, despite public debates and polling in Seoul and Tokyo. Civilian nuclear cooperation deals, such as those supporting uranium enrichment in South Korea or energy programs in Saudi Arabia, remain subject to IAEA safeguards and US export controls that block rapid weaponization. Technical timelines for enrichment, testing, and integration exceed the narrow window, sustaining trader consensus around the low probability of breakout. Residual risks include abrupt alliance shifts or secret acceleration, though even these face substantial diplomatic and sanctions hurdles before resolution.