When U.S. and Soviet leaders once met, high-stakes negotiations focused on reducing the threat of nuclear war. The language spoken, often in initials rather than words, differed greatly from today's talks.

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ABM Treaty: In 1972, President Nixon and Soviet General Secretary Leonid Brezhnev signed the Anti-Ballistic Missile treaty that limited strategic missile defense systems. On Dec. 13, 2001, President Bush announced that the United States would withdraw from the pact to allow continued development of a missile defense system.

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ICBM: Intercontinental ballistic missile.

SLBM: Submarine-launched ballistic missile.

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SALT I: The Strategic Arms Limitation Treaty, also signed in 1972, to limit offensive arms. The agreement barred the two superpowers from starting construction of fixed land-based intercontinental ballistic missile launchers after July 1, 1972, and converting older weapons that were deployed prior to 1964. It also limited submarine-launched ballistic missiles.

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MAD: Mutual assured destruction was a Cold War doctrine described by former Defense Secretary Robert McNamara (Kennedy and Johnson administrations) in which full-blown use of nuclear weapons by one side would result in the total destruction of both sides.

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START I and START II: The purpose of the Strategic Arms Reduction Treaties was to limit the number of delivery systems — launchers for ICBMs and SLBMs — as well as nuclear warheads in the U.S. and Soviet arsenals. Negotiations took place during the 1980s. The START I treaty was signed in July 1991, and shortly thereafter the Soviet Union collapsed. President George H.W. Bush and Russian leader Boris Yeltsin signed the START II treaty on Jan. 3, 1993, that called for deeper cuts.

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MIRVs: Multiple Independently Targetable Re-entry Vehicles.

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"Trust, but verify": A phrase used by former President Reagan in describing negotiations with the Soviets.