entered into force between 1963 and 1990 limit but do not ban such tests. In 1996, the U.N.
General Assembly adopted the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which would
ban all nuclear explosions. In 1997, President Clinton sent the CTBT to the Senate, which
rejected it in October 1999. In a speech in Prague in April 2009, President Obama said, “My
administration will immediately and aggressively pursue U.S. ratification of the Comprehensive
Test Ban Treaty.” However, the Administration focused its efforts in 2010 on securing Senate
advice and consent to ratification of the New Strategic Arms Reduction Treaty (New START).
The Administration has indicated it wants to begin a CTBT “education” campaign with a goal of
securing Senate advice and consent to ratification, but there have been no hearings on the treaty
in the 111th or 112th Congresses. As of December 2011, 182 states had signed the CTBT and 156,
including Russia, had ratified it. However, entry into force requires ratification by 44 states
specified in the treaty, of which 41 had signed the treaty and 36 had ratified. Seven conferences
have been held to facilitate entry into force, most recently on September 23, 2011.