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 (NPT), is a landmark international treaty and the foundation of nuclear nonproliferation. Its goals are to:

  • prevent new countries from getting nuclear weapons
  • encourage the peaceful use of nuclear energy
  • lead to eventual nuclear disarmament


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

Over the next 20 years, as UN representatives deliberated over how to prevent the proliferation of nuclear weapons, four more countries obtained nuclear weapons: the USSR, UK, France, and China. By August 1967, after much negotiation, the United States and the Soviet Union submitted a draft nonproliferation treaty to a UN-sponsored disarmament committee. Over the next several months, the draft was revised, reflecting the concerns of non-nuclear states. The UN General Assembly approved a resolution supporting the final text, and opened up the treaty for signature in July 1968.


59 countries signed on to the NPT upon its release, and now 190 are a party to it. Despite this nearly universal agreement, the number of countries with nuclear weapons has grown.

When the treaty was first signed, there were only five nuclearized countries, officially labeled “nuclear weapon states.” Today however, four more countries have or are believed to have nuclear weapons and are not party to the NPT: India, Israel, Pakistan, and North Korea. (While the first three never signed the treaty, North Korea signed it in 1985 and withdrew in 2003.)

Treaty parties disagree on the effectiveness and role of the Nonproliferation Treaty. Many countries without nuclear weapons believe it’s unfair that while they have rejected nukes, the first set of countries to obtain nuclear weapons still have not fulfilled their promise to disarm.

Some scholars say the NPT has helped in creating a norm, or acceptable rule of behavior, around the use of nuclear power. But others have called the treaty “much less influential in international security than is commonly believed.” One common criticism is that the treaty does not reflect the nature of today’s nuclear world. For example, it does not mention the possibility of nuclear weapons falling into the hands of nonstate actors like terrorist groups.

Nevertheless, parties to the treaty hold review conferences every five years to discuss what progress can be made on both nonproliferation and eventual disarmament.


In addition to the NPT, countries have come together since the 1960s to ensure that nuclear weapons do not enter certain regions. They created Nuclear-Weapon-Free Zones (NWFZs), which are areas of the world where countries pledge not to build, receive, test, or store nuclear weapons. NWFZs do not prevent the use of nuclear technology for peaceful purposes.

The idea of setting up an area where nuclear weapons are banned was first introduced in 1958 when Poland suggested a plan to get rid of nuclear weapons and create a nuclear-weapon-free zone in Central Europe. But NWFZs officially got their start through the NPT, which recognized the right of countries to make these zones (as Mongolia did for itself in 2000).

There are five treaties that have created NWFZs in Latin America, the South Pacific, Southeast Asia, Africa, and Central Asia. Together, these zones cover 115 countries, and they span the entire Southern Hemisphere and parts of the Northern Hemisphere.

Three treaties keep other zones free from nuclear weapons:

  • The Seabed Treaty bans weapons of mass destruction on the ocean floor.
  • The Outer Space Treaty bans weapons of mass destruction from Earth’s Orbit, the Moon, or any other objects in outer space.
  • The Antarctic Treaty bans any military action in Antarctica, including the testing of nuclear weapons.
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