Comprehensive Nuclear-Test-Ban Treaty (CTBT) is an international agreement prohibiting all tests of nuclear weapons. The United Nations General Assembly approved the treaty in 1996, and more than 180 nations have signed it. To enter into force, the agreement must be ratified (formally approved) by 44 nations named in the treaty. All 44 countries have nuclear reactors (devices for producing nuclear energy). The group also includes all nations that either have, or are suspected of having, nuclear weapons. Among these countries are China, France, India, Israel, Pakistan, Russia, the United Kingdom, and the United States. Several of the 44 specified countries, including China and the United States, have not ratified the treaty, and India, Pakistan, and North Korea have not signed it. However, the nations that have signed the pact are expected to abide by it even if it does not formally go into effect.
Attempts to negotiate a test ban treaty started in 1958 and, over the years, resulted in several agreements that banned certain kinds of nuclear tests. In 1963, for example, the Soviet Union, the United Kingdom, and the United States signed the Limited Test Ban Treaty. This agreement prohibited the testing of nuclear weapons in the atmosphere, in outer space, and underwater but permitted testing underground. In 1974, the Threshold Test Ban Treaty prohibited the testing of the most powerful explosive devices.
The Soviet Union stopped testing nuclear weapons in 1985, and Russia continued the Soviet policy after the Soviet Union broke apart in 1991. By the summer of 1996, China and France had declared that they would no longer test nuclear weapons. These events—and U.S. support for a total ban on testing—encouraged diplomats to promote the Comprehensive Nuclear-Test-Ban Treaty. The treaty gradually became acceptable to almost all parties, with the exception of India, Pakistan, and North Korea. In September 1996, a special session of the United Nations General Assembly approved the treaty.
In 1998, India conducted a short series of nuclear tests, its first since 1974. Later in 1998, Pakistan, India’s neighbor and rival to the northwest, responded with its first nuclear test ever. These tests raised fears that a nuclear arms race had begun between the two countries. In addition, North Korea conducted nuclear weapons tests during the early 2000’s. Russia, which had ratified the Comprehensive Nuclear-Test-Ban Treaty in 2000, revoked its ratification in 2023.
