For more than three decades, the United States has refrained from conducting explosive nuclear tests, a policy that has shaped both domestic security strategies and global arms control efforts. This longstanding moratorium, rooted in a mix of legislative action, scientific innovation, and international diplomacy, now faces renewed scrutiny as the world approaches the 80th anniversary of the atomic bombings that ended World War II. Amidst this reflection, Charles Oppenheimer—grandson of J. Robert Oppenheimer, the famed “father of the atomic bomb”—is calling for urgent dialogue to prevent a new nuclear arms race, echoing the warnings and hopes of his grandfather’s generation.
The U.S. approach to nuclear stewardship has evolved dramatically since its last explosive test. According to the Department of Energy’s National Nuclear Security Administration (NNSA), the country relies on the Science-Based Stockpile Stewardship program, which blends advanced computer simulations, laboratory experiments, and subcritical testing at the Nevada National Security Site (NNSS). As of August 23, 2025, the NNSA maintains that there are “no technical reasons” to resume full-scale nuclear testing. Instead, the U.S. arsenal’s safety, security, and effectiveness are ensured through this rigorous, non-explosive approach.
This policy is not merely a matter of scientific consensus. Congressional action has provided the legal backbone: a 1992 amendment prohibited U.S. underground nuclear tests after September 30, 1996, unless another country conducted one first. While India, Pakistan, and North Korea have tested nuclear devices since then, successive U.S. administrations—including those of Donald Trump and Joe Biden—have upheld the moratorium. Both presidents reaffirmed this stance in their respective Nuclear Posture Reviews, underscoring the moratorium as a “cornerstone of U.S. nuclear strategy.”
Internationally, the landscape is complex. The United States signed the Comprehensive Test Ban Treaty (CTBT) in 1996, which would prohibit all nuclear explosions, but the Senate rejected its ratification in 1999. As of today, 187 countries have signed the CTBT and 178 have ratified it, yet the treaty remains unenforced because key nuclear-capable states—including the U.S., China, and Iran—have not completed ratification. Russia, which ratified the CTBT in 2000, withdrew its ratification in 2023, raising additional concerns about the future of global test bans.
These international developments have not gone unnoticed in Washington. U.S. officials have publicly expressed doubts regarding Russia’s and China’s adherence to “zero-yield” nuclear test standards, citing limited transparency and what they describe as possible preparations for expanded testing. In response, the NNSA has announced plans to increase the pace of subcritical nuclear experiments to three per year by the end of the decade, a move that reflects both scientific curiosity and strategic caution.
Against this backdrop, policy debates in the U.S. remain vigorous. Some advocates argue that renewing U.S. nuclear testing could strengthen negotiating leverage with rivals or enhance deterrence. Yet others, including former Energy Secretary Ernest Moniz, warn that such a move would risk triggering a global arms race, undermining decades of nonproliferation efforts, and creating health and environmental risks for Nevada communities. The Congressional Research Service recently concluded that lawmakers will likely continue to grapple with the delicate balance between test readiness, arsenal modernization, and international commitments.
Despite the moratorium, the United States retains the technical capability to resume nuclear testing within 24 to 36 months if ordered by the president. For now, however, current policy remains firmly in favor of restraint, with the moratorium serving as a key element of nuclear strategy.
Yet, as the expiration of the New START treaty looms—set for February 2026—the risk of a new arms race is palpable. The New START treaty, the last remaining arms control pact between the U.S. and Russia, limits each nation to no more than 1,550 strategic nuclear warheads and provides for verification measures such as inspections. As of August 23, 2025, Russia holds approximately 4,309 nuclear warheads, the United States approximately 3,700, and China about 600. The prospect of losing the New START treaty, according to Paul Dean, a former senior U.S. arms control official, could increase the chances of a "catastrophic" nuclear misinterpretation or miscalculation between the U.S. and Russia, as reported by USA TODAY.
For Charles Oppenheimer, these developments are deeply personal. The 50-year-old tech investor and founder of the Oppenheimer Project has long felt a responsibility to address the legacy of his grandfather, whose leadership on the Manhattan Project ushered in the atomic age. Speaking with USA TODAY, Oppenheimer said, "I, as an Oppenheimer, often get asked on Aug. 6 and Aug. 9 about those symbolic dates," referencing the anniversaries of the Hiroshima and Nagasaki bombings. But he draws particular attention to August 17, 1945, when his grandfather and fellow Manhattan Project physicists penned a top-secret letter to Secretary of War Henry Stimson. In it, they warned that the U.S. could not maintain a monopoly on nuclear weapons and urged, "It is our unanimous and urgent recommendation to you that ... all steps be taken, all necessary international arrangements be made, to this end."
Charles Oppenheimer calls this letter an example of "incredible foresight," noting that his grandfather and his colleagues "understood what was at stake, what was going to happen and how to prevent ... an arms race." The physicists recognized that nuclear weapons would only become more powerful—indeed, the U.S. detonated the world’s first hydrogen bomb in November 1952, an explosion physicists estimated was 1,000 times larger than the Hiroshima bomb.
Today, Oppenheimer is advocating for a nuclear summit in 2025, urging leaders of the U.S., Russia, and China to engage in trilateral discussions on nuclear threat reduction. His call comes after the August 15, 2025, summit between President Donald Trump and Russian President Vladimir Putin in Anchorage, Alaska, failed to yield any publicly acknowledged progress on arms control. Despite the lack of breakthroughs, Oppenheimer remains optimistic, citing President Trump’s willingness to negotiate with both China and Russia as a rare opportunity. "It doesn't matter how much we hate each other, (or) how many wars or skirmishes we're in – you have to talk about the (nuclear) weapons issue, no matter what the circumstances are," he said.
Oppenheimer even offered, with a chuckle, to host a dinner to encourage personal connections between world leaders. "I don't have the right to invite world leaders to dinner, but I'm doing it anyway ... trying to back the idea that there should be trilateral discussions about nuclear threat reduction," he told USA TODAY.
As the expiration of New START approaches and the possibility of a new arms race looms, the voices urging restraint and dialogue grow ever more urgent. The lessons of history, echoed by the Oppenheimer family and reinforced by decades of policy, suggest that the stakes have never been higher—and the window for action never narrower.