Détente in the 1970s

The 1970s saw something that had seemed impossible a decade earlier: the United States and the Soviet Union sitting down together to negotiate written limits on their nuclear arsenals, American and Soviet astronauts shaking hands in orbit, and 35 nations signing an agreement committing themselves to respect human rights. This relaxation of tension — "détente", from the French verb meaning to loosen — did not end the Cold War. Rivalries continued in the developing world, and by the end of the decade the whole project was in trouble. But for roughly a decade, the superpowers accepted that direct confrontation was too dangerous and too costly, and tried to manage their competition rather than win it.

This lesson covers détente from its origins in the late 1960s to its collapse at the end of the 1970s. It is important Edexcel 1HI0 Paper 2 territory: examiners regularly set Question 1 (consequences) and Question 3 (importance) questions on SALT I, the Helsinki Accords and the reasons détente failed. You should be able to explain what détente meant, why both sides wanted it, what the main agreements were, and why by 1979 it was effectively over.

What détente meant — and why it was wanted

Détente was not peace and it was not friendship. It was the practical acceptance that Mutually Assured Destruction meant the two superpowers could never afford a direct war with each other, and that their competition therefore had to be managed. It involved regular high-level summits, arms-control treaties, economic contacts and symbolic acts of cooperation.

By the late 1960s, both sides had reasons to want détente:

• Cost. The arms race and global competition was expensive. The US was spending around 8–9% of GDP on defence in the late 1960s; the Soviet Union, on some estimates, over 15%.
• Strategic parity. By around 1970, the USSR had caught up with the US in numbers of ICBMs. This meant that a negotiated ceiling protected both sides rather than advantaging one.
• Vietnam. The US was trapped in an unwinnable war in South-East Asia. President Nixon wanted Soviet help in pressuring North Vietnam, and he wanted to be free to concentrate on East Asia and China.
• Sino-Soviet split. By 1969 the USSR and the People's Republic of China had fought actual border skirmishes along the Ussuri River. Moscow feared a two-front conflict. Reducing tension with the US became strategically attractive.
• China opening. Nixon and his National Security Adviser Henry Kissinger pursued "triangular diplomacy". Nixon's visit to Beijing in February 1972 was explicitly designed to worry Moscow and to push it toward negotiation with the US — "playing the China card".
• European stability. West Germany's Chancellor Willy Brandt was pursuing Ostpolitik — a normalisation of relations with East Germany and Eastern Europe. The Moscow Treaty (August 1970), Warsaw Treaty (December 1970) and Basic Treaty with East Germany (December 1972) accepted post-war European borders and reduced East-West tension in Europe.

SALT I, May 1972

The centrepiece of early détente was the Strategic Arms Limitation Talks (SALT). Negotiations opened in Helsinki in November 1969 and culminated in two agreements signed by Nixon and Brezhnev at a summit in Moscow on 26 May 1972. Together they are known as SALT I.

SALT I had two parts:

Treaty	Duration	Main content
ABM Treaty	Indefinite (later withdrawn by US, 2002)	Limited each side to two Anti-Ballistic Missile sites (later reduced to one). Prevented a destabilising defensive arms race.
Interim Agreement on Offensive Arms	5 years	Froze numbers of ICBM and SLBM launchers at existing levels. Did not limit warheads, or bombers.

Under the Interim Agreement the USA was allowed 1,054 ICBMs and 656 SLBMs; the USSR was allowed 1,618 ICBMs and 740 SLBMs. The Soviet higher ceiling reflected the fact that Soviet missiles generally carried smaller warheads and were less accurate, while US technological advantages (especially MIRV — multiple independently targetable re-entry vehicles) were not covered by the agreement.

SALT I was the first arms-limitation treaty the superpowers had ever signed. It did not reduce arsenals but it froze their expansion in key categories and — crucially, through the ABM Treaty — locked in the logic of Mutually Assured Destruction. If neither side could defend itself, neither could safely launch.

The Moscow Summit, May 1972

The SALT I signing was only one element of a wider Moscow Summit (22–30 May 1972) that redefined superpower diplomacy. Nixon was the first sitting US president to visit Moscow. The summit produced:

• SALT I (ABM Treaty and Interim Agreement).
• A "Basic Principles Agreement" pledging both sides to avoid military confrontation and to conduct relations on the basis of peaceful coexistence.
• Agreements on cooperation in science, technology, environment, health and space.
• A commercial agreement boosting US-Soviet trade.

The symbolism mattered. A decade after the Cuban Missile Crisis, the President of the United States stood at the Kremlin signing binding agreements with the General Secretary of the Communist Party. For both populations, détente was real and tangible.

Helsinki Accords, August 1975

The second great monument of détente was the Helsinki Final Act, signed on 1 August 1975 by 35 nations — every European state except Albania, together with the USA, Canada and the USSR.

The Accords were organised into four "baskets":

• Basket I — Security: recognition of post-war European borders, renunciation of the threat or use of force, non-intervention in internal affairs.
• Basket II — Economics: cooperation in trade, industry, science and environment.
• Basket III — Humanitarian: commitments on human rights, freedom of information, family reunification, free movement of peoples.
• Basket IV: follow-up meetings (what later became the Helsinki process, eventually the OSCE).

Each side interpreted Helsinki according to its interests: