What is the CTBT?

Exploring the Comprehensive Nuclear Test Ban Treaty

A complete, global halt to nuclear weapons test explosions has been a central objective of the United States since it was proposed by President Dwight Eisenhower in 1958.

The 1963 Limited Test Ban Treaty prohibited nuclear weapons test explosions in the atmosphere and underwater, but the arms race continued with underground nuclear weapons test explosions. This allowed Russia, the United States, and others to field test new and more deadly warhead designs. To date: eight countries have conducted 2,052 nuclear weapons test explosions. The United States has conducted 1,030—more than all others combined.

Following the end of the Cold War in 1991, Russia stopped nuclear testing, and in 1992 President George H. W. Bush halted new warhead production and the Congress approved a U.S. nuclear test moratorium.

Three years of negotiations on a comprehensive ban treaty followed, and, on September 23, 1996, the United States was the first nation to sign the Comprehensive Nuclear Test Ban Treaty (CTBT), which “prohibits any nuclear weapon test explosion or any other nuclear explosion,” and establishes a global monitoring network and the option of short-notice, on-site inspections that improves capabilities to detect and deter cheating.

The CTBT has now been signed by 182 nations, including the U.S., Russia, China, Great Britain and France, and ratified by 153. The CTBT’s entry into force awaits ratification by nine states, including the United States, China, India, Indonesia, Israel, and Pakistan.

Today, there is no military requirement for new U.S. nuclear weapons capabilities that might require the resumption of U.S. nuclear testing. The U.S. nuclear weapons laboratories do not need (nor have they ever relied upon) nuclear explosive testing to maintain the effectiveness of the U.S. arsenal.

Even though the United States has already assumed most CTBT-related responsibilities, it cannot reap the full security benefits of the CTBT until the Senate approves the Treaty by a two-thirds majority.

A global verifiable ban on testing would constrain the ability of nuclear-armed states, such as China, to develop new and more deadly nuclear weapons. Without nuclear weapon test explosions, would-be nuclear-armed nations—like Iran—would not be able to proof test the more advanced, smaller nuclear warhead designs that could be used to arm ballistic missiles.

Once the CTBT enters into force, the United States will also have the option to seek short-notice, on-site inspections that will help detect and deter possible cheating by others.

The Obama administration has urged the Senate to reconsider the CTBT in light of new information supporting ratification that has emerged since the Senate’s brief debate and rejection the CTBT in 1999. As President Reagan’s Secretary of State, George Shultz, said in April 2009: [Republicans] might have been right voting against it some years ago, but they would be right voting for it now, based on these new facts…”

Today, a growing list of bipartisan leaders and security experts agree that the CTBT would the ability of others to build new and more deadly nuclear weapons that could pose a threat to American security.

As Dr. Siegfried Hecker, former Director of the Los Alamos National Laboratory has argued: “The single most important reason to ratify the CTBT is to stop other countries from improving their arsenals. We gain substantially more from limiting other countries than we lose by giving up testing….”

The U.S. Stockpile Stewardship Program has demonstrated that the U.S. nuclear arsenal can be maintained safely and effectively under a CTBT. Since 1994, Life Extension Programs have refurbished and recertified major warhead types without nuclear test explosions. Key plutonium parts in warheads have been shown to last 85-100 years, much longer than previously thought, and limited production capacity has been established to remanufacture new parts when needed, making new-design “replacement” warheads unnecessary.

Not only do the nuclear weapons laboratories have a deeper understanding of the arsenal than during the nuclear testing era, but they also have more resources than ever. The Obama administration’s unprecedented $85 billion, 10-year plan for upgrading the nuclear weapons complex provides a long-term strategy and more than enough funding to continue to maintain the U.S. arsenal effectively.

Today, no other country can confidently conduct additional nuclear weapons tests that could pose a threat to U.S. security. The treaty’s International Monitoring System, together with U.S. national technical means of verification, can detect militarily significant tests. However, unless it ratifies the Treaty, the United States cannot take advantage of the system’s full benefits, including on-site inspections.

Over the past decade, national and international test monitoring capabilities have improved. North Korea’s nuclear test explosions in 2006 and 2009 demonstrated that the CTBT verification system is working well and can detect very small explosions with high confidence.

The United States has more to gain from the CTBT than any other nation. Without positive U.S. action on the CTBT, the risks of nuclear weapons proliferation and the resumption of testing will only grow.

Congressional Research Service Report on the CTBT



Congressional Research Service Report on the CTBT – August 3, 2011