The Collapse of Detente: SALT II and the Invasion of Afghanistan, 1979
SALT II was a second arms control treaty, signed by President Carter and Soviet leader Leonid Brezhnev in June 1979, which set further limits on the number of strategic nuclear weapons each superpower could hold. It represented the high point of detente, but its progress through the US Senate was overtaken by events: in December 1979 the USSR invaded Afghanistan to support its struggling communist government against Islamist mujahideen rebels, and Carter, viewing the invasion as proof of continued Soviet expansionism, withdrew SALT II from the Senate before it could be ratified. As a result, SALT II never came into legal force, even though both superpowers broadly continued to observe its limits informally, and the invasion of Afghanistan marked the point at which detente collapsed into a renewed period of Cold War hostility.
Before you start
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Method
- Learn SALT II precisely: signed by President Carter and Brezhnev in June 1979, it set further, tighter limits on the number of strategic nuclear weapons (such as ICBMs and bombers) each side could hold, building on SALT I from 1972.
- Learn why SALT II was never ratified: the US Senate must approve treaties before they take legal force, and Carter withdrew SALT II from the Senate in December 1979, immediately after the USSR invaded Afghanistan, because ratifying an arms treaty with an invading power would have been politically impossible.
- Learn the Afghanistan invasion as the direct cause of SALT II's failure: the USSR sent troops into Afghanistan in December 1979 to prop up its client communist government against mujahideen rebels, and Carter interpreted this as proof the USSR remained an expansionist power that could not be trusted to keep to arms limits.
- Learn what actually happened to SALT II's limits in practice: although never legally ratified, both superpowers broadly continued to observe its numerical limits informally for some years, showing the treaty had some lasting influence even without formal legal force.
- For 'write a narrative account' questions, link SALT II's signing to its collapse in a single connected story: the treaty was signed in a spirit of continuing detente in mid-1979, but within six months the invasion of Afghanistan destroyed the political conditions that had made ratification possible.
- For 'explain two consequences' questions, distinguish the consequence for arms control specifically (SALT II's failed ratification) from the wider consequence for the Cold War (the definite end of detente and a return to hostility).
Worked example
Write a narrative account analysing the key events from the signing of SALT II in June 1979 to its withdrawal from the US Senate. You may use the following information to help write your answer: the Soviet invasion of Afghanistan; President Carter's response. You must also use information of your own.
- Plan the sequence: the signing of SALT II (June 1979), the Soviet invasion of Afghanistan (December 1979), and Carter's decision to withdraw the treaty from Senate ratification.
- Open with the signing: Carter and Brezhnev signed SALT II in June 1979, agreeing further limits on strategic nuclear weapons, representing the continuing spirit of detente built up since the early 1970s.
- Link forward: 'However, only six months later, in December 1979, the USSR invaded Afghanistan to support its struggling communist government against mujahideen rebels, an action that shocked the US government.'
- Link forward again: 'As a direct result, Carter concluded the USSR could not be trusted to keep to an arms limitation treaty while acting in this expansionist way, and he withdrew SALT II from the Senate before it could be ratified.'
- Close with the outcome: 'Consequently, SALT II never became legally binding, and the invasion of Afghanistan is generally seen as the moment detente finally collapsed, ushering in a new, more hostile period of the Cold War.'
- Check the account shows the treaty's failure as a direct, explained consequence of the invasion, not two separate, unconnected facts.
Practice questions
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Q1Who signed SALT II, and when?Show answer
Answer: President Carter and Soviet leader Leonid Brezhnev, in June 1979.
Q2What did SALT II set limits on?Show answer
Answer: The number of strategic nuclear weapons, such as ICBMs and bombers, each superpower could hold.
Q3Why did SALT II never come into legal force?Show answer
Answer: Because Carter withdrew it from the US Senate, which must ratify treaties, after the USSR invaded Afghanistan in December 1979.
Q4Why did the USSR invade Afghanistan in December 1979?Show answer
Answer: To support its struggling communist government there against Islamist mujahideen rebels.
Q5Did the superpowers stop observing SALT II's limits once it failed to be ratified?Show answer
Answer: Not entirely - both sides broadly continued to observe its numerical limits informally for some years, even without legal ratification.
Q6What is generally seen as the event that marked the end of detente?Show answer
Answer: The Soviet invasion of Afghanistan in December 1979.
Exam-style questions
Written in the style of a GCSE History exam paper, with a full mark scheme.
Explain two consequences of the Soviet invasion of Afghanistan for the SALT II treaty and arms control.
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Explain two of the following: (a) The importance of the Soviet invasion of Afghanistan for the failure of SALT II. (b) The importance of SALT II for detente in the years 1972-79. (c) The importance of the US Senate's role for the failure of SALT II. You must answer on two options.
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