The Anti-Ballistic Missile (ABM) Treaty was established between the United States and the Soviet Union to restrict and locate only two ABM deployment areas in such a nature that they cannot become the basis for developing a nationwide ABM defense. This left each state unchallenged by the other state’s penetration capabilities of their retaliatory missile forces. Quantitative and qualitative limits were also imposed on the ABM systems that could potentially be deployed. Every five years, the United States and the Soviet Union/Russian Federation would hold meetings in Geneva to review and modify the Treaty arrangements. In 2001, U.S. president George Bush submitted a formal notification of intent to repeal the treaty and in 2002, the United States withdrew from the ABM Treaty.
Opened for Signature: 26 May 1972
Entry into force: 3 October 1972
Official Text: http://www.state.gov/t/avc/trty/101888.htm#narrative
Status and Signatories: http://www.state.gov/t/avc/trty/101888.htm#text
ACA Backgrounder: https://www.armscontrol.org/factsheets/abmtreaty