The U.S. has maintained a voluntary moratorium on nuclear explosive testing since 1992, relying instead on the Science-Based Stockpile Stewardship Program for warhead certification. Recent developments include President Trump's October 2025 directive to prepare testing on parity with alleged Chinese and Russian activities, followed by congressional provisions in the fiscal 2026 National Defense Authorization Act that could lift the ban upon foreign tests. In late September 2026, the National Nuclear Security Administration conducted a non-nuclear chemical explosive experiment at the Nevada National Security Site to refine detection of low-yield or decoupled detonations, without producing a nuclear yield. Diplomatic discussions with China on verification and site visits continue alongside working-level P5 talks. Technical readiness timelines of up to 36 months, Senate oversight, and the absence of confirmed preparations keep trader-implied probabilities low for any explosive test by late 2026 dates.