The Comprehensive Test Ban Treaty (CTBT) is a multilateral treaty prohibiting the testing of nuclear weapons. By banning nuclear explosions, the treaty seeks to prevent the harmful effects of radioactive fall-out on society and the environment. The treaty also intends to prevent new countries from acquiring and testing nuclear weapons technology and discourage the production of new types of nuclear weapons. The CTBT puts international norms against testing into binding international law and represents a critical move toward nuclear disarmament. 

The CTBT has not entered into force and awaits ratification by nine key countries, including the United States. Though the U.S. was first to sign the treaty in 1996, it has not been ratified. The Senate considered the treaty in 1999 but ratification efforts failed, effectively halting the treaty’s progress. The Obama administration has pledged its support for the CTBT, and Senate Committee on Foreign Relations Chairman John Kerry has stated that efforts are underway to achieve ratification.

• Official Treaty Text: Comprehensive Nuclear Test-Ban Treaty - Preparatory Commission for the Comprehensive Nuclear-Test-Ban-Treaty Organization
• Briefing Book: Now More Than Ever - The Case for the Comprehensive Nuclear Test-Ban Treaty - Arms Control Association
• Report: Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments - Congressional Research Service
• Statement: Secretary-General Ban Ki-Moon’s statement on the urgency of the entry into force of the Comprehensive Nuclear-Test-Ban Treaty - UN.org, June 2009
• Article: Renew the Drive for CTBT Ratification - Washington Quarterly, April 2009

". . . I was honored to be the first of 146 leaders to sign the Comprehensive Test Ban Treaty, our commitment to end all nuclear tests for all time -- the longest-sought, hardest-fought prize in the history of arms control.  . . . Our common goal should be to enter the CTBT into force as soon as possible, and I ask for all of you to support that goal."
~ Bill Clinton, U.S. President

"I am of the belief, if you could have a ban on all [nuclear] testing that everybody could have confidence in, it would be a very, very fine thing to stop this. . ."
~ Dwight D. Eisenhower, U.S. President