**US allies face steep technical, diplomatic, and political barriers to acquiring nuclear weapons by December 31, 2026.** No formal indigenous weapons programs have advanced among NATO members or major non-NATO allies such as Japan, South Korea, or Saudi Arabia, despite ongoing debates over extended deterrence and civilian nuclear cooperation. Recent US-Saudi and US-South Korea civil nuclear frameworks permit limited enrichment for energy purposes under safeguards, yet explicitly stop short of weapons development and remain subject to NPT obligations, IAEA monitoring, and export controls. Elite and public opinion in Japan and South Korea continues to favor reliance on the US nuclear umbrella over independent arsenals, while realistic breakout timelines—from fissile material production to tested devices—extend well beyond the remaining months. Trader consensus at 95%+ for “No” reflects these constraints and the absence of credible breakout signals. Scenarios that could still shift odds include a verified Iranian nuclear test prompting rapid Saudi hedging, a sudden US security withdrawal triggering allied decisions, or the revelation of undisclosed programs, though each faces substantial verification and time hurdles before year-end.