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Why did the superpowers pursue detente in the 1970s and why did it collapse?
Detente in the 1970s, including the Strategic Arms Limitation Talks (SALT I 1972, SALT II 1979), the Helsinki Accords (August 1975), and the collapse of detente by the end of the decade
A focused answer to the HSC Modern History Cold War dot point on detente, the Strategic Arms Limitation Talks (SALT I, 26 May 1972; SALT II, 18 June 1979), the Helsinki Final Act (1 August 1975), the role of Nixon, Kissinger, Brezhnev, Carter, and the collapse of detente by the late 1970s through the Soviet invasion of Afghanistan (December 1979) and the failure of SALT II ratification.
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What this dot point is asking
NESA expects you to explain why and how the superpowers moved from confrontation to managed competition in the 1970s, the central agreements (SALT I, Helsinki, SALT II), and why the policy collapsed by the end of the decade.
The answer
Why detente, 1968 to 1972
Five conditions made detente possible. First, strategic parity: by 1969 Soviet ICBM numbers (1,028) exceeded American (1,054 by 1970), ending the American superiority that had let Kennedy use it as leverage in 1962. Mutual Assured Destruction made arms control rational.
Second, the Sino-Soviet split: armed clashes on the Ussuri River (March 1969) created the possibility of an American opening to Beijing. Kissinger's secret July 1971 trip and Nixon's 21 to 28 February 1972 visit produced the Shanghai Communique. Moscow's incentive to deal with Washington increased.
Third, the Vietnam War: the United States needed Soviet help to extract from Vietnam. The Paris Peace Accords (27 January 1973) were partly a product of Soviet leverage on Hanoi.
Fourth, West German Ostpolitik under Willy Brandt: the Moscow Treaty (12 August 1970), Warsaw Treaty (7 December 1970), Basic Treaty with East Germany (21 December 1972), and the Four Power Berlin Agreement (3 September 1971) recognised the post-war territorial settlement, removing the German question as the central European flashpoint.
Fifth, Soviet economic stress: the planned economy was slowing. Imports of grain and technology required Western credit.
SALT I, 26 May 1972
The Strategic Arms Limitation Talks began in Helsinki on 17 November 1969. Nixon, Kissinger, Brezhnev, Gromyko, and Defence Minister Grechko reached agreement at the Moscow Summit of 22 to 30 May 1972.
The package signed on 26 May contained:
- Anti-Ballistic Missile Treaty (ABM Treaty): each side limited to two ABM sites of 100 launchers (reduced to one site of 100 launchers in a 1974 protocol). The Soviet Galosh system around Moscow and the American Safeguard system at Grand Forks remained. The ABM Treaty held until American withdrawal in June 2002.
- Interim Agreement on Strategic Offensive Arms: capped American ICBMs at 1,054 and Soviet ICBMs at 1,618; American SLBMs at 656 and Soviet at 740. Heavy bombers were uncounted. MIRVs were not capped.
The Basic Principles of Mutual Relations (29 May 1972) committed both sides to "peaceful coexistence" and to "avoid military confrontations." The Treaty on the Prevention of Nuclear War (Washington, 22 June 1973) added consultative obligations.
Helsinki Final Act, 1 August 1975
The Conference on Security and Cooperation in Europe began in 1972, drawing 35 countries (all European states except Albania, plus the United States and Canada). The Final Act was signed at Helsinki on 1 August 1975.
Three "baskets":
- Basket I: Declaration on Principles, including the inviolability of post-1945 borders, peaceful settlement of disputes, non-intervention, and respect for human rights and fundamental freedoms.
- Basket II: economic, scientific, technological, and environmental cooperation.
- Basket III: cooperation in humanitarian and other fields, including family reunification, information flow, and educational exchange.
The Soviet bloc valued Basket I as Western recognition of the Eastern bloc's borders (the eastern German border, the Baltic annexations). The West valued Basket III as a lever on human rights inside the Soviet bloc.
The Final Act produced dissident movements citing Helsinki: the Moscow Helsinki Group (12 May 1976) under Yuri Orlov; Charter 77 in Czechoslovakia (1 January 1977) under Vaclav Havel, Jan Patocka, and Jiri Hajek; the Helsinki Watch Committee in the United States (1978, later Human Rights Watch). Soviet repression of these groups discredited Soviet good faith.
SALT II, 18 June 1979
SALT II negotiations resumed at Geneva from late 1972. The Vladivostok Accord (Ford-Brezhnev, 23 to 24 November 1974) set framework limits. The Carter administration proposed deeper cuts in March 1977; the Soviets rejected and negotiations resumed on the Vladivostok basis.
The Vienna Summit (15 to 18 June 1979) produced SALT II. Aggregate caps: 2,400 strategic delivery vehicles initially, reducing to 2,250 by 1981. Sub-limits on MIRVed ICBMs (820), MIRVed SLBMs (1,200), and heavy bombers carrying air-launched cruise missiles. New types of ICBM were restricted to one per side.
The Senate Foreign Relations Committee approved SALT II in November 1979 by 9 to 6. The full Senate vote was deferred and never held after the Soviet invasion of Afghanistan (24 to 27 December 1979). Both sides observed SALT II limits until 1986.
Collapse of detente
Six factors collapsed detente. First, Soviet adventurism in the Third World: Angola (1975 to 1976, with Cuban troops), the Horn of Africa (1977 to 1978), Vietnam-Cambodia, Nicaragua (1979).
Second, the human rights challenge: Carter's January 1977 letter to Andrei Sakharov, the Soviet exile, and the Helsinki-inspired dissident movement made cooperation politically toxic.
Third, the Euromissile crisis: Soviet deployment of SS-20 mobile MIRVed intermediate-range missiles from 1976 (eventually 441) panicked NATO. The 12 December 1979 NATO dual-track decision combined an offer to negotiate with a commitment to deploy 572 American Pershing II and ground-launched cruise missiles in Europe by 1983.
Fourth, the Iranian Revolution (1 February 1979) and the hostage crisis (4 November 1979 to 20 January 1981) destabilised American foreign policy.
Fifth, the Soviet invasion of Afghanistan (24 to 27 December 1979) was framed by Carter as "the most serious threat to peace since the Second World War." Grain embargo, Moscow Olympics boycott, withdrawal of SALT II.
Sixth, Reagan's 1980 election (4 November) ended the political constituency for detente. Reagan called the USSR an "evil empire" (Orlando, 8 March 1983) and pursued military build-up.
Timeline
| Date | Event | Significance |
|---|---|---|
| Mar 1969 | Ussuri clashes | Sino-Soviet split |
| 17 Nov 1969 | SALT begins | Talks open |
| 21 to 28 Feb 1972 | Nixon in Beijing | Triangle |
| 26 May 1972 | SALT I and ABM Treaty | Strategic cap |
| 1 Aug 1975 | Helsinki Final Act | European settlement |
| 1 Jan 1977 | Charter 77 | Helsinki dissent |
| From 1976 | SS-20 deployment | Euromissile crisis |
| 18 Jun 1979 | SALT II | Vienna treaty |
| 12 Dec 1979 | NATO dual-track | Pershing II decision |
| 24 to 27 Dec 1979 | Soviet invasion of Afghanistan | Detente ends |
| 4 Nov 1980 | Reagan elected | Detente over |
Historiography
Raymond Garthoff's Detente and Confrontation (1985, revised 1994) is the standard scholarly account. John Lewis Gaddis's Strategies of Containment (1982, revised 2005) places detente within American strategic doctrine. Vladislav Zubok's A Failed Empire (2007) covers the Soviet side. Odd Arne Westad's The Global Cold War (2005) emphasises Third World causes of collapse.
Common exam traps
Treating detente as friendship. It was managed competition. SS-20s were deployed during detente; proxy wars continued in Angola.
Misdating Helsinki. 1 August 1975, not 1972 or 1977.
Forgetting the dual-track decision. 12 December 1979 NATO commitment to deploy Pershing II reshaped European security before Reagan.
In one sentence
Detente between 1969 and 1979 produced SALT I (26 May 1972) and the ABM Treaty, the Helsinki Final Act (1 August 1975) trading Western recognition of post-1945 borders for Soviet human rights commitments that produced Charter 77 and the Helsinki Watch movement, and SALT II (18 June 1979) capping MIRV warheads, but collapsed under Soviet SS-20 deployment, Third World adventurism, the dissident challenge, the NATO dual-track decision (12 December 1979), the Soviet invasion of Afghanistan (December 1979), and Reagan's election (November 1980).
Past exam questions, worked
Real questions from past NESA papers on this dot point, with our answer explainer.
Practice (NESA)15 marksAssess the achievements and failures of detente in the 1970s.Show worked answer →
A 15-mark "assess" needs a weighted judgement.
Achievements. SALT I (Moscow, 26 May 1972) capped strategic launchers at existing levels and restricted anti-ballistic missile systems to two sites (one later). The Basic Principles Agreement (1972) committed both sides to peaceful coexistence. The Helsinki Final Act (1 August 1975) accepted post-1945 European borders, opened economic exchange, and committed signatories to human rights through Basket III. SALT II (Vienna, 18 June 1979) capped MIRV warheads.
Failures. SALT II was never ratified by the United States Senate. The Helsinki human rights commitments produced dissident movements (Helsinki Watch in the United States, Moscow Helsinki Group, Charter 77 in Czechoslovakia, 1977) that the Soviet bloc repressed. Soviet build-up of SS-20 intermediate-range missiles (from 1976) panicked NATO into the December 1979 dual-track decision. The Soviet invasion of Afghanistan (24 December 1979) ended the political possibility of detente.
Judgement. Detente stabilised the strategic competition at strategic parity but failed to manage proxy conflicts in the Third World and Soviet defence industrial momentum. Its institutional gains (the OSCE process, the ABM Treaty until 2002) outlasted the political relationship.
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