The Agni II, an intermediate-range ballistic missile, is rolled out during the Republic Day parade in New Delhi, India on January 26, 2002.

The Treaty on the Nonproliferation of Nuclear Weapons, known commonly as the Nuclear Nonproliferation Treaty (NPT), is a landmark international treaty and the foundation of nuclear nonproliferation. Its goals are to 

  • prevent countries that do not already have a nuclear arsenal from getting nuclear weapons, 
  • support the peaceful use of nuclear energy, and 
  • lead to eventual nuclear disarmament in countries that already possess nuclear weapons.

What led to the creation of the NPT?

The United States was the first country to use atomic weapons. In the final days of World War II, it dropped two bombs on the Japanese cities Hiroshima and Nagasaki, killing tens of thousands of people in a matter of minutes. Less than six months later, in 1946, the UN General Assembly called for the total elimination of nuclear weapons.

Yet over the next twenty years, as UN representatives deliberated over how to prevent the proliferation, or spread, of nuclear weapons, four more countries obtained nuclear weapons: the Soviet Union, the United Kingdom, France, and China.

By August 1967, after many negotiations, the United States and the Soviet Union submitted a draft nonproliferation treaty to a UN committee focused on disarmament. The Cold War was in full swing, and all eyes were on the two countries; together they held most of the world’s nuclear weapons and viewed each other as an existential threat. Over the next several months, the draft was revised to reflect the concerns, such as eventual elimination of nuclear weapons, that countries without nuclear weapons had. The General Assembly then opened the treaty for signature in July 1968.

Countries that have—and have not—joined the NPT

Fifty-nine countries signed the NPT when it opened for signature; the treaty now has 190 parties. Yet despite this nearly universal agreement, the number of countries with nuclear weapons has grown. 
When the treaty was opened for signatures, only five countries were identified as “nuclear-weapon states.” Today however, four more countries, which are not party to the NPT, possess or are believed to possess nuclear weapons: India, Israel, Pakistan, and North Korea. (While the first three never joined the treaty, North Korea joined the NPT in 1985 but withdrew in 2003.)

NPT Ratification

See which countries joined the treaty and when.

Does the NPT work? 

Reviews of the NPT are mixed. Some experts say the NPT has helped create a norm, or acceptable rule of behavior, around the use of nuclear power by putting the goal of nonproliferation into writing. But others say the NPT is not as influential as it’s believed to be. And countries that have joined the treaty disagree on how effective it actually is at preventing nuclear proliferation. Here is how the NPT measures up to its goals:

  • Preventing the spread of nuclear weapons: Although the number of nuclear weapons in the world has shrunk since its peak in the 1980s, more countries have nuclear weapons now than before. Also, the NPT does not address the possibility of nuclear weapons falling into the hands of terrorist groups. Such a threat exists in a nuclear-armed country like Pakistan, where terrorist groups can operate relatively freely and those seeking to acquire nuclear weapons could have easier access to them.
  • Supporting the peaceful use of nuclear energy: The NPT encourages countries to provide each other with nuclear materials for peaceful purposes, such as harnessing alternative energy sources. But it doesn’t provide a strong safeguard against rogue countries using nuclear technology to develop weapons. To address these shortcomings, additional conditions have been added to the treaty and accepted by 135 countries. These extra rules allow the International Atomic Energy Agency, the UN agency tasked with monitoring the peaceful use of nuclear power worldwide, to make “surprise” inspections at nuclear enrichment sites to make sure that these sites are not being used to build weapons. But not everyone has agreed to these rules.
  • Achieving nuclear disarmament (eventually): Several countries considered launching nuclear programs and eventually decided against doing so, such as Brazil and Argentina. Meanwhile, South Africa created a stockpile and then destroyed it. And countries such as Ukraine transferred the weapons they had to Russia. Still, the five countries that had nuclear weapons when the treaty went into effect—China, France, Russia, the United Kingdom, and the United States—still maintain sizeable nuclear arsenals, and many countries without nuclear weapons argue it’s unfair that the nuclear weapons states have not yet disarmed. 

Because of these gaps, many countries have signed separate agreements and treaties of their own. 

The reality of living in a world with nuclear weapons means some countries want protection from nuclear weapons even if they ultimately believe in the goal of nonproliferation. One way countries handle this dilemma is by agreeing to security guarantees, usually pledges from a nuclear-armed country to protect non–nuclear armed allies in the event of an attack. 

Other countries want more control over nuclear weapons and materials than the NPT offers, so they draft agreements with countries that share similar goals to tackle specific issues related to nuclear power. Australia, for example, has agreements with nineteen countries to guarantee that any uranium it sells to them is used only for peaceful purposes and is not transferred to third parties. 

Do we still need the NPT? 

Yes. While newer agreements address specific issues that the NPT’s framework does not, they haven’t replaced the NPT yet. In addition, countries that are party to the NPT are continuously working to improve it: every five years, the parties meet to discuss how to achieve its goals of nonproliferation and eventual disarmament, a practice that gives this foundational agreement fresh air and room to grow.
 

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