Détente: SALT, Helsinki & the Limits of Peace
What Was Détente?
Détente is a French word meaning the relaxation of tension. In the context of the Cold War, it refers to the period during the 1970s when the USA and USSR actively tried to improve relations and reduce the risk of nuclear war. Both superpowers had reasons to pursue détente.
The USA wanted détente because the Vietnam War (1955–75) had been enormously costly in both lives and money, reducing public appetite for confrontation. The arms race was ruinously expensive, and the Cuban Missile Crisis had shown how close the world could come to nuclear destruction. The USSR also wanted to reduce military spending. Its economy was struggling under the burden of the arms race, and the Sino-Soviet split (the breakdown in relations between the USSR and China) meant the USSR now faced potential enemies on two fronts. Both sides recognised that managing their rivalry was safer and cheaper than escalating it.
SALT 1 (1972)
The first Strategic Arms Limitation Talks resulted in SALT 1, signed by President Nixon and Soviet leader Brezhnev in May 1972. The treaty froze the number of ICBMs and submarine-launched ballistic missiles (SLBMs) each side could hold at their current levels for five years. It also included the Anti-Ballistic Missile (ABM) Treaty, which limited each side to two missile defence sites.
SALT 1 was significant because it was the first agreement between the superpowers to limit nuclear weapons. However, it only froze existing numbers — it did not reduce them. It also did not cover new technologies like MIRVs (missiles carrying multiple warheads), so the arms race continued in new forms.
The Helsinki Accords (1975)
In August 1975, 35 countries including the USA and USSR signed the Helsinki Accords. These were not a legally binding treaty but a set of agreements covering three areas, known as “baskets.”
Basket 1 — Security: All signatories accepted the post-war borders in Europe, meaning the West formally recognised Soviet control of Eastern Europe. Basket 2 — Economic cooperation: East and West agreed to increase trade, exchange technology and improve transport links. Basket 3 — Human rights: All signatories agreed to respect basic human rights, including freedom of thought, speech and movement.
The Helsinki Accords were the high point of détente. The USSR gained Western recognition of its European borders (Basket 1), but the human rights commitments (Basket 3) later became a powerful tool for dissidents in Eastern Europe to challenge communist governments — something the USSR had not anticipated.
SALT 2 (1979)
Negotiations for a second SALT treaty took seven years. SALT 2 was signed by President Carter and Brezhnev in June 1979. It set equal limits on the number of strategic nuclear delivery vehicles (ICBMs, SLBMs and bombers) each side could hold — a maximum of 2,250 each. It also limited the number of MIRVed missiles.
However, SALT 2 was never ratified by the US Senate. In December 1979, the Soviet Union invaded Afghanistan, and Carter withdrew the treaty from Senate consideration as a protest. Détente was effectively over.
Détente reduced tensions but never resolved the fundamental differences between the superpowers. The arms race continued in new forms (MIRVs, cruise missiles). The USSR continued to support communist movements worldwide. The USA continued to support anti-communist governments, even dictatorships. Human rights commitments in the Helsinki Accords were largely ignored by the Soviet Union. When strategic interests clashed — as in Afghanistan — détente collapsed quickly. Critics argued détente was merely a pause, not a genuine peace.
Other Arms Control Treaties
Détente also built on earlier agreements reached after the Cuban Missile Crisis. The Outer Space Treaty (1967) prevented the placement of nuclear weapons in space. The Nuclear Non-Proliferation Treaty (1968) aimed to stop the spread of nuclear weapons to non-nuclear states. Together with SALT 1 and the Helsinki Accords, these agreements created a framework of arms control that, while imperfect, helped manage the superpower rivalry throughout the 1970s.