Anti-Ballistic Missile Treaty (1972)


Bilateral ratified treaty of "unlimited duration" between the U.S. and U.S.S.R. limiting each side's anti-ballistic missile (ABM) systems in order to prevent the deployment of nationwide ABM defenses, or a base for such a system. Each country is restricted to a single deployment area of 100 ABM launchers and missiles. The treaty prohibits the development, testing and deployment of space-based, sea-based, air-based and mobile land-based systems and components. Compliance is monitored by national technical means of verification and overseen by a Standing Consultative Commission. The treaty entered into force on October 3, 1972.

On December 13, 2001, President George W. Bush formally notified Russia and three former Soviet republics that it had invoked Article 15 of the Anti-Ballistic Missile (ABM) Treaty to withdraw from the pact. On June 13, 2002, the United States formally withdrew from the treaty. Ground breaking on a test site located at Delta Junction, Alaska for the U.S. missile defense system occured a few days later. The treaty had banned such construction.Delta Junction, Alaska, breaking ground on a test site for the administration's $64 billion missile defense system.


In the Treaty on the Limitation of Anti-Ballistic Missile Systems the United States and the Soviet Union agree that each may have only two ABM deployment areas, 1so restricted and so located that they cannot provide a nationwide ABM defense or become the basis for developing one. Each country thus leaves unchallenged the penetration capability of the others retaliatory missile forces.

The Treaty permits each side to have one limited ABM system to protect its capital and another to protect an ICBM launch area. The two sites defended must be at least 1,300 kilometers apart, to prevent the creation of any effective regional defense zone or the beginnings of a nationwide system.

Precise quantitative and qualitative limits are imposed on the ABM systems that may be deployed. At each site there may be no more than 100 interceptor missiles and 100 launchers. Agreement on the number and characteristics of radars to be permitted had required extensive and complex technical negotiations, and the provisions governing these important components of ABM systems are spelled out in very specific detail in the Treaty and further clarified in the "Agreed Statements" accompanying it.

Both Parties agreed to limit qualitative improvement of their ABM technology, e.g., not to develop, test, or deploy ABM launchers capable of launching more than one interceptor missile at a time or modify existing launchers to give them this capability, and systems for rapid reload of launchers are similarly barred. These provisions, the Agreed Statements clarify, also ban interceptor missiles with more than one independently guided warhead.

There had been some concern over the possibility that surface-to-air missiles (SAMs) intended for defense against aircraft might be improved, along with their supporting radars, to the point where they could effectively be used against ICBMs and SLBMs, and the Treaty prohibits this. While further deployment of radars intended to give early warning of strategic ballistic missile attack is not prohibited, such radars must be located along the territorial boundaries of each country and oriented outward, so that they do not contribute to an effective ABM defense of points in the interior.

Further, to decrease the pressures of technological change and its unsettling impact on the strategic balance, both sides agree to prohibit development, testing, or deployment of sea-based, air-based, or space-based ABM systems and their components, along with mobile land-based ABM systems. Should future technology bring forth new ABM systems "based on other physical principles" than those employed in current systems, it was agreed that limiting such systems would be discussed, in accordance with the Treatys provisions for consultation and amendment.