1992 – The United States conducts its last underground nuclear test, marking the end of a decades‑long testing program that it now relies on simulations for warhead reliability[6].

1996 – China publicly declares a self‑imposed nuclear‑test moratorium and signs the Comprehensive Nuclear‑Test‑Ban Treaty (CTBT), though the treaty never enters force because key states, including the United States, do not ratify it[3].

1998‑2006 – The previous longest global test‑free interval runs from Pakistan’s 1998 test to North Korea’s first test in 2006, establishing a benchmark for future hiatuses[2].

2006 – North Korea conducts its inaugural nuclear explosion, breaking the post‑Cold‑War testing lull and beginning a series of six tests through 2017[2].

September 3, 2017 – North Korea carries out its most recent nuclear test, the last of its six detonations to date[2].

June 22, 2020 – U.S. intelligence identifies a magnitude‑2.75 seismic event 720 km from China’s Lop Nur site, interpreting the waveform as a covert underground nuclear explosion that employed “decoupling” to mask a yield of only a few hundred tons[1][3].

2022 – The U.S. Department of Defense releases a strategy warning that China’s expanding arsenal could give it novel coercive options in regional crises[1].

2023 – Russia revokes its ratification of the CTBT, citing an “imbalance” with the United States and signaling a willingness to resume testing if other powers do so[5].

2024 – A Defense Intelligence Agency (DIA) report warns that China’s modernization program aims to field a completely new nuclear force, including multiple‑warhead missiles and low‑yield tactical weapons[1].

October 31, 2025 – President Donald Trump posts on Truth Social that the Department of War will “begin nuclear weapons testing immediately,” framing the move as a response to rival programs[5].

October 2025 – Trump plans an “equal‑basis” testing discussion with Chinese President Xi Jinping, echoing his earlier call for the United States to match peer‑state testing activities[3].

November 10, 2025 – At a Vienna CTBT meeting, U.S. Chargé d’Affaires Howard Solomon declares that the United States will resume nuclear testing “on an equal basis” with other nuclear powers, citing alleged violations by Russia and China since 2019[4].

December 2, 2025 – The United States and Russia publicly threaten to resume nuclear testing; Putin tells the Security Council that Russia will take reciprocal action if the U.S. or any CTBT signatory conducts a test[5].

December 18, 2025 – Solomon reiterates that low‑yield “supercritical” tests could evade the global monitoring network, and he points to U.S. reports of suspected activity at China’s Lop Nur and Russia’s Novaya Zemlya sites[4].

February 5, 2026 – The New START treaty expires, removing the last major bilateral arms‑control constraint on U.S. and Russian strategic arsenals and prompting U.S. officials to push for a new three‑way treaty with China and Russia[4][6].

January 15, 2026 – The world marks an eight‑year, four‑month, eleven‑day nuclear‑test hiatus—the longest since the 1945 Trinity explosion—while analysts warn that the lapse of New START could trigger rapid deployment of thousands of additional warheads[2].

February 17, 2026 – Assistant Secretary of State Christopher Yeaw tells a Hudson Institute audience that a remote Kazakhstan station recorded a 2.75‑magnitude blast on June 22, 2020, whose waveform “is entirely not consistent with an earthquake” and matches a nuclear detonation signature[6].

February 18, 2026 – A senior U.S. official warns that foregoing nuclear testing would place America at an “intolerable disadvantage” against peer rivals, citing the 2020 Chinese event as evidence of a covert test program[3].

February 21, 2026 – U.S. intelligence concludes that the 2020 Chinese test signals a drive toward a new nuclear arsenal, including next‑generation warheads capable of carrying multiple miniaturized payloads and low‑yield tactical nukes intended for regional scenarios such as a Taiwan conflict[1].

2026 onward – The United States plans to conduct subcritical experiments that do not produce a self‑sustaining chain reaction, while urging China to join a three‑way treaty to replace New START; experts caution that U.S. testing could lower the threshold for other states, including China and India, to develop advanced warheads[5][6].