US extended deterrence commitments, reinforced through trilateral diplomacy with Japan and South Korea plus NATO arrangements, continue to anchor allied security strategies and discourage independent nuclear programs. Recent civilian nuclear cooperation deals with Saudi Arabia and approvals for South Korean naval reactors reflect interest in fuel cycle technology but remain constrained by NPT obligations, enrichment limits, and IAEA safeguards, with no verified weapons programs advancing toward operational capability. Technical and political hurdles, including Senate oversight and historical nonproliferation precedents, make breakout timelines exceed the 2027 horizon for any US ally. Shifts could arise only from abrupt alliance erosion or acute regional crises prompting rapid policy reversals.