The U.S. has maintained a voluntary moratorium on nuclear explosive testing since 1992, with the last such detonation occurring that year at the Nevada National Security Site. President Trump’s October 2025 directive to resume testing “on an equal basis” with China and Russia raised the possibility of a return, yet no nuclear chain-reaction test has been confirmed in the subsequent year. The most recent related activity, a September 30, 2026, NNSA chemical high-explosive experiment at the Nevada site, focused exclusively on refining detection of low-yield or decoupled foreign tests rather than conducting one. Historical preparation timelines of 24–36 months, Senate concerns, and the absence of announced test dates or site preparations keep implied probabilities low across active market dates. Any shift would require verifiable executive action and credible reporting of an actual detonation.