1963: Three of the four nuclear powers sign a limited treaty that bans most, but not all, nuclear weapons testing.

The Limited Nuclear Test Ban Treaty was signed in Moscow by the United States, Soviet Union and Great Britain. The fourth nation to possess “the bomb,” France, did not sign the treaty. Nor did China, which was just over a year away from exploding its first nuclear device.

The treaty prohibited all nuclear testing in the atmosphere, in outer space and underwater. It still allowed underground testing as long as the radioactive debris generated by the detonation was contained within the territorial limits of the testing state.

The treaty was seen as much as a means of safeguarding the environment as it was a way of easing Cold War tensions. But those tensions, fraught as they were with political brinkmanship and mutual mistrust, played a major role in the extended negotiations that ensued. In the end, it took eight years to forge an agreement.

Fear of environmental contamination as the result of nuclear fallout was the original impetus for pushing a test-ban treaty. By the mid-1950s the thermonuclear weapons being so blithely tested in places like Bikini Atoll and Siberia dwarfed the atomic bombs used against Japan a decade earlier. In some cases, the actual yields of these detonations were badly underestimated — the 1954 Bikini test by the United States a case in point — raising fears that unchecked testing would result in catastrophic, worldwide nuclear fallout.

The detonation in the Bikini test was expected to have the power of about 8 million tons of TNT. The actual yield was almost double that, and the fallout extended well beyond any predictions. To make matters worse, a Japanese fishing vessel believed to be safely outside the danger zone was contaminated and its crew stricken with radiation sickness.

In a world already terrified by the prospect of nuclear annihilation, the idea of being poisoned by fallout was real enough. Scientists talked openly about the possibility of massive contamination and the genetic damage that would surely follow. The pressure to do something mounted, from nuclear and non-nuclear states alike.

With the entire world watching in May 1955, the U.N. Disarmament Commission convened its Subcommittee of Five — including the Soviet Union, United States, France, Britain and Canada — to get things rolling. Other nations weighed in, introducing various resolutions to the U.N. General Assembly.

At one point, the Soviet Union proposed an outright ban on all nuclear testing, an idea that was rejected by the United States. Eight difficult years of negotiations were under way.

Finally, with all of the major hurdles removed, the final treaty was negotiated in 10 days. It was signed in Moscow on Aug. 5, 1963, by Secretary of State Dean Rusk for the United States, Foreign Minister Andrei Gromyko for the Soviet Union, and Lord Home for Great Britain.

U.S. congressional debate followed, and the Senate ratified the test ban treaty in late September by a vote of 80-19. President John F. Kennedy added his signature Oct. 7.

By the time the treaty went into force Oct. 10, 1963, 108 nations — including those with nuclear aspirations of their own — had affixed their signatures to the document. It would remain the most effective arms control measure on the books until the conclusion of the first SALT treaty between the United States and the Soviet Union in 1972.

Even with the advent of new controls and the partial dismantling of nuclear arsenals in both the United States and post-Soviet Russia, the 1963 test ban treaty, which was given no expiration date, remains in effect. New signatories were still being added as late as 1988.

An attempt was made in 1991 to amend the treaty and make it a comprehensive test ban by prohibiting all nuclear testing. As it had decades earlier, the United States refused to accept any changes.

Source: Atomicarchive.com, various

Photo: President John F. Kennedy, surrounded by U.S. cabinet officials and senators, prepares to sign the Nuclear Test Ban Treaty with the Soviet Union in 1963. (Corbis)

See Also:

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• Jan. 7, 1953: The Big Boom
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