Successes and Failures of Détente in the Cold War

US President Reagan and Soviet president Gorbachev shake hands
Reagan and Gorbachev Meet At Their First Summit In Geneva. Dirck Halstead / Getty Images

From the late 1960s to the late 1970s, the Cold War was highlighted by a period known as “détente” – a welcome easing of tensions between the United States and the Soviet Union. While the period of détente resulted in productive negotiations and treaties on nuclear arms control and improved diplomatic relations, events at the end of the decade would bring the superpowers back to the brink of war.

Use of the term “detent”— French for “relaxation”— in reference to an easing of strained geopolitical relations dates back to the 1904 Entente Cordiale, an agreement between Great Britain and France that ended centuries of off-and-on war and left the nations strong allies in World War I and thereafter.

In the context of the Cold War, U.S. presidents Richard Nixon and Gerald Ford called détente a “thawing out” of U.S.-Soviet nuclear diplomacy essential to avoiding a nuclear confrontation.

Détente, Cold War-Style

While U.S.-Soviet relations had been strained since the end of World War II, fears of war between the two nuclear superpowers peaked with the 1962 Cuban Missile Crisis. Coming so close to Armageddon motivated leaders of both nations to undertake some of the world’s first nuclear arms control pacts, including the Limited Test Ban Treaty in 1963.

In reaction to the Cuban Missile Crisis, a direct telephone line – the so-called red telephone – was installed between the U.S. White House and the Soviet Kremlin in Moscow allowing leaders of both nations to communicate instantly in order to reduce the risks nuclear war.

Despite the peaceful precedents set by this early act of détente, rapid escalation of the Vietnam War during the mid-1960s increased Soviet-American tensions and made further nuclear arms talks all but impossible.

By the late 1960s, however, both the Soviet and U.S. governments realized one big and unavoidable fact about the nuclear arms race: It was hugely expensive. The costs of diverting ever-larger portions of their budgets to military research left both nations facing domestic economic hardships.

At the same time, the Sino-Soviet split – the rapid deterioration of relations between the Soviet Union and the People’s Republic of China – made becoming friendlier with the United States look like a better idea to the USSR.

In the United States, the soaring costs and political fallout of the Vietnam War caused policymakers to see improved relations with the Soviet Union as a helpful step in avoiding similar wars in the future.

With both sides willing to at least explore the idea of arms control, the late 1960s and early 1970s would see the most productive period of détente.

The First Treaties of Détente

The first evidence of détente-era cooperation came in the Nuclear Nonproliferation Treaty (NPT) of 1968, a pact signed by several of the major nuclear and non-nuclear power nations pledging their cooperation in stemming the spread of nuclear technology.

While the NPT did not ultimately prevent the proliferation of nuclear arms, it paved the way for the first round of Strategic Arms Limitations Talks (SALT I) from November 1969 to May 1972. The SALT I talks yielded the Antiballistic Missile Treaty along with an interim agreement capping the number of intercontinental ballistic missiles (ICBMs) each side could possess.

In 1975, two years of negotiations by the Conference on Security and Cooperation in Europe resulted in the Helsinki Final Act. Signed by 35 nations, the Act addressed a range of global issues with Cold War implications, including new opportunities for trade and cultural exchange, and policies promoting the universal protection of human rights.

The Death and Re-Birth of Détente

Unfortunately, not all, but most good things must end. By the end of the 1970s, the warm glow of U.S.-Soviet détente began to fade away. While diplomats of both nations agreed on a second SALT agreement (SALT II), neither government ratified it. Instead, both nations agreed to continue to adhere to the arms reduction provisions of the old SALT I pact pending future negotiations.

As détente broke down, progress on nuclear arms control stalled completely. As their relationship continued to erode, it became clear that both the U.S. and the Soviet Union had overestimated the extent to which détente would contribute to an agreeable and peaceful end of the Cold War.

Détente all but ended when the Soviet Union invaded Afghanistan in 1979. President Jimmy Carter angered the Soviets by increasing U.S. defense spending and subsidizing the efforts of anti-Soviet Mujahideen fighters in Afghanistan and Pakistan.

The Afghanistan invasion also led the United States to boycott the 1980 Olympics held in Moscow. Later the same year, Ronald Reagan was elected President of the United States after running on an anti-détente platform. In his first press conference as president, Reagan called détente a “one-way street that the Soviet Union has used to pursue its aims.”

With the Soviet invasion of Afghanistan and the election of détente-opposed President Reagan, attempts to implement provisions of the SALT II agreement were abandoned. Arms control talks would not resume until Mikhail Gorbachev, being the only candidate on the ballot, was elected president of the Soviet Union in 1990.

With the United States developing President Reagan’s so-called “Star Wars” Strategic Defense Initiative (SDI) ant-ballistic missile system, Gorbachev realized that the costs of countering U.S. advances in nuclear weapons systems, while still fighting a war in Afghanistan would eventually bankrupt his government.

In the face of the mounting costs, Gorbachev agreed to new arms control talks with President Reagan. Their negotiation resulted in the Strategic Arms Reduction Treaties of 1991 and 1993. Under the two pacts known as START I and START II, both nations not only agreed to stop making new nuclear weapons but also to systematically reduce their existing weapons stockpiles.

Since enactment of the START treaties, the number of nuclear weapons controlled by the two Cold War superpowers has been significantly reduced. In the United States, the number of nuclear devices dropped from a high of over 31,100 in 1965 to about 7,200 in 2014. The nuclear stockpile in Russia/the Soviet Union fell from about 37,000 in 1990 to 7,500 in 2014.

The START treaties call for continued nuclear arms reductions through the year 2022, when stockpiles are to be cut to 3,620 in the United States and 3,350 in Russia.