Limited Test Ban Treaty
In 1958, as a first step toward a test-ban treaty, both the U.S. and Soviet Union temporarily suspended nuclear testing. This informal moratorium on nuclear testing was ended in September 1961 by the Soviet Union. Two weeks later, the U.S. responded by conducting its own test series. The resumption of nuclear testing produced much radioactive and political fallout. The public concern about the fallout danger finally produced enough political pressure to force negotiations of a test-ban treaty.
The Limited Test Ban Treaty (LTBT) was a trilateral agreement between the U.S., U.S.S.R., and U.K., which halted atmospheric, underwater and outer space nuclear tests. Since 1963, an additional 113 countries have signed the treaty. There are two major non-signers, France and China, although they both signed the Comprehensive Test Ban Treaty in 1996.
Ironically, the LTBT indirectly contributed to the nuclear arms race because it kept the magnitude of the world's stockpiles from public awareness.