The Nuclear Nonproliferation Treaty

Since 1970, the Treaty on the Non-Proliferation of Nuclear Weapons has helped prevent the spread of nuclear weapons, and it has defined much of the work at Los Alamos National Laboratory.

April 22, 2022

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President Johnson LBJ Presidential Library

On July 1, 1968, the world was in turmoil. American troops were embroiled in the sixth month of the Vietnam War Tet Offensive, and the American death toll for the conflict as a whole had reached the tens of thousands. Martin Luther King Jr. and Robert F. Kennedy had both recently been assassinated. Czechoslovakia was only weeks away from a bloody invasion by Soviet forces. And amidst all of this was the ever-present Cold War fear of nuclear war. But on this day, something positive—something peaceful—happened. On July 1, 1968, the United States and the Soviet Union, along with the United Kingdom, signed the Treaty on the Non-Proliferation of Nuclear Weapons, more commonly known as the Non-Proliferation Treaty or NPT.

The NPT, which went into effect on March 5, 1970, was born of the Cold War, with the goal of averting “the devastation that would be visited upon all mankind by a nuclear war.” Although the Cold War between the United States and the Soviet Union continued until the early 1990s, the NPT helped prevent an arms race that had the potential to involve virtually every country in the world. The treaty also required nations in possession of nuclear weapons, including the United States and the Soviet Union, to reduce those arms.

The main components of the NPT are that

  • Nuclear Weapon States—the five countries that possessed nuclear weapons at the time the NPT was signed—will not give nuclear weapons or nuclear weapons information to Non-Nuclear Weapon States. Also, Non-Nuclear Weapon States must not accept nuclear weapons or nuclear weapons information.
  • Non-Nuclear Weapon States commit to accept safeguards on transfers of nuclear technology for peaceful purposes. These safeguards are determined and enforced by the International Atomic Energy Agency (IAEA).
  • all signatories work “toward the further development of the applications of nuclear energy for peaceful purposes.”
  • all signatories work toward an overall global reduction of nuclear weapons and the avoidance of another nuclear arms race.
  • the treaty would be valid for 25 years (until 1995), at which point its future would be evaluated.
Johnson Treaty
President Johnson signed the NPT in the East Room of the White House. He called the event a "very reassuring and hopeful moment in the relations among nations." Photo: LBJ Presidential Library

The NPT was difficult to negotiate because it allowed some states to keep nuclear weapons while requiring other states to give up the ability to pursue them. But, after many rounds of negotiation, the treaty was finalized.

For almost three decades, two nuclear states, China and France, did not sign. They both acceded to the treaty in 1992, first China in March and then France in August. Several nonnuclear states also refrained from signing, notably India, Israel, Pakistan, Saudi Arabia, and South Africa, nations that, in 1968, were on the verge of becoming nuclear states (two of which did—India in 1974 and Pakistan in 1983). South Africa signed in 1991, admitting two years later to a nuclear program and then dismantling all of its weapons by 1994. Current non-parties include India, Israel, Pakistan, South Sudan, and North Korea, the last of which originally signed but withdrew in 2003.

The NPT’s first expiration date was also its last. On May 11, 1995, the treaty was extended without an end date, so the states party to the treaty still abide by its regulations and agreements. The treaty’s extension continues to require Nuclear Weapon States to pursue disarmament and arms control agreements, which necessitates a great deal of work in treaty verification and monitoring, much of which is done at Los Alamos National Laboratory. “For more than 50 years, work at Los Alamos in nonproliferation and arms control has been grounded in the NPT,” says Nancy Jo Nicholas, associate Laboratory director for Global Security. “I am proud of our world-renowned expertise in support of this important treaty, particularly in international safeguards, export control, and arms control verification.”

“The Laboratory’s support for the NPT spans most of its history and activities, from providing the technologies necessary for detection, monitoring, and verification, to support for the IAEA, to providing the means for deterrence, which has been one of the most effective U.S. nonproliferation policies,” says Will Tobey, director of the Lab’s Office of National Security and International Studies.

From the time it went into effect, the NPT has provided some stability in the often unstable landscape of nuclear weapons. It prevented, and continues to prevent, the spread of nuclear weapons, and it motivates its signatories to prioritize the development of nuclear energy for peaceful purposes, from nuclear power plants to power for outer space missions. This landmark treaty continues in perpetuity, keeping the world safer.