The Proliferation Problem Is Back
Washington Must Adapt Its Playbook for a New Era of Nuclear Risk
Mariano-Florentino Cuéllar, Ernest J. Moniz, and Meghan L. O’Sullivan
September 25, 2025
In 1964, China detonated a 22-kiloton nuclear device at a test site in the arid northwestern Xinjiang region—and the political fallout reached Washington. Worried about the prospect that many countries around the world would soon gain nuclear weapons, U.S. President Lyndon Johnson convened a committee of seasoned foreign policy leaders to advise him on what Washington should do to prevent proliferation. Led by the former U.S. deputy secretary of defense Roswell Gilpatric, the group asked what an increase in nuclear-armed states would mean for U.S. security, what assurances the United States could realistically offer states that decided to forgo nuclear weapons, and how far Washington should go to prevent more states from acquiring them.
The Gilpatric committee’s conclusion was unanimous: averting the spread of nuclear weapons to any state, friend or foe, should be a top national security priority. To achieve that end, the committee provided a policy blueprint that Washington then went about implementing. Acting on the group’s advice, U.S. officials began negotiating multilateral nonproliferation treaties and agreements, including, controversially, accords with the Soviet Union. The United States also developed measures to cajole and coerce other countries into remaining nonnuclear, including extending security assurances, supporting civilian scientific endeavors, and threatening to cut off military support and impose economic penalties on proliferating states. Thanks in large part to such initiatives, U.S. efforts to combat proliferation over the last 60 years have succeeded more often than they have failed. Only nine states possess nuclear weapons, and only North Korea has acquired them in the twenty-first century.
But the nuclear landscape is changing in ways that are bringing proliferation back to the fore. An increasingly powerful China is scaling up its nuclear arsenal. Russia has backstopped its war in Ukraine with threats of nuclear use. Iran’s nuclear program was set back by recent U.S. and Israeli attacks, but it was not destroyed. U.S. allies, worried about their security and unsure about Washington’s commitment to their defense, are also mulling going nuclear. And evolving technologies such as artificial intelligence are making it easier than ever for states to build the bomb. Against this backdrop, the Cold War–era tools and tactics that Washington has long relied on to manage proliferation challenges are eroding. The international treaties and regimes that govern nuclear issues, particularly the Nuclear Nonproliferation Treaty (NPT), are badly frayed. Great-power cooperation on nuclear dangers has stalled.
https://www.foreignaffairs.com/united-states/proliferation-problem-back
