On August 5, 1963, after more than eight years of difficult negotiations, the United States, the United Kingdom, and the Soviet Union signed the Limited Nuclear Test Ban Treaty.

bikini atoll atomic test photo

The destruction of Hiroshima and Nagasaki by atomic bombs marked the end of World War II and the beginning of the nuclear age.  As tensions between East and West settled into a Cold War, scientists in the United States, Great Britain, and the Soviet Union conducted tests and developed more powerful nuclear weapons.

In 1959, radioactive deposits were found in wheat and milk in the northern United States. As scientists and the public gradually became aware of the dangers of radioactive fallout, they began to raise their voices against nuclear testing. Leaders and diplomats of several countries sought to address the issue.

Attempts to Negotiate a Treaty

In May 1955, the United Nations Disarmament Commission brought together the United States, the United Kingdom, Canada, France, and the Soviet Union to began negotiations on ending nuclear weapons testing.

Conflict soon arose over inspections to verify underground testing. The Soviet Union feared that on-site inspections could lead to spying that might expose the Soviets' vastly exaggerated claims of the number of deliverable nuclear weapons. As negotiators struggled over differences, the Soviet Union and the United States suspended nuclear tests—a moratorium that lasted from November 1958 to September 1961.

Kennedy Opposes Testing

John F. Kennedy had supported a ban on nuclear weapons testing since 1956. He believed a ban would prevent other countries from obtaining nuclear weapons, and took a strong stand on the issue in the 1960 presidential campaign. Once elected, President Kennedy pledged not to resume testing in the air and promised to pursue all diplomatic efforts for a test ban treaty before resuming underground testing. He envisioned the test ban as a first step to nuclear disarmament.

President Kennedy met with Soviet Premier Khrushchev in Vienna in June 1961, just five weeks after the humiliating defeat of the U.S.-sponsored invasion of Cuba at the Bay of Pigs. Khrushchev took a hard line at the summit. He announced his intention to cut off Western access to Berlin and threatened war if the United States or its allies tried to stop him. Many U.S. diplomats felt that Kennedy had not stood up to the Soviet premier at the summit and left Khrushchev with the impression that he was a weak leader.