During the Cold War, the period of détente marked a temporary easing of tensions between the United States and the Soviet Union. It began in the late 1960s and continued through much of the 1970s, characterized by arms control agreements, increased diplomatic communication, and a cautious but hopeful shift away from direct confrontation. However, by the end of the decade, this fragile period of reduced hostility began to unravel. Understanding how détente ended involves examining key geopolitical shifts, failed agreements, mutual suspicions, and rising conflicts that ultimately reignited Cold War hostilities. The collapse of détente set the stage for a renewed arms race and a return to intense superpower rivalry in the 1980s.
Background of Détente
Détente, which means relaxation in French, was a strategic approach initiated primarily by U.S. President Richard Nixon and Soviet leader Leonid Brezhnev. Its aim was to avoid nuclear confrontation and build cooperation in certain areas such as trade, technology, and arms control. Milestones of this period included:
- The Strategic Arms Limitation Talks (SALT I) in 1972
- The Anti-Ballistic Missile Treaty (ABM Treaty)
- The Helsinki Accords in 1975
Despite these agreements, détente always carried an undercurrent of distrust. Both sides continued building their military capabilities, and ideological competition never disappeared. The system depended on careful management, and when external and internal pressures mounted, détente began to falter.
Growing Tensions in the Late 1970s
As the decade progressed, several developments contributed to the erosion of trust between the superpowers. These included global events, political changes, and growing opposition within both countries.
The Human Rights Issue
One of the earliest cracks in détente came from disagreements over human rights. The 1975 Helsinki Accords, signed by over 30 nations including the U.S. and USSR, included a commitment to respect human rights and fundamental freedoms. However, the Soviet Union continued suppressing political dissidents and religious groups. The U.S. Congress and American public opinion became increasingly critical of Soviet actions, viewing them as violations of the agreement.
This focus on human rights became a major issue for American policymakers, especially under President Jimmy Carter, who made human rights a cornerstone of his foreign policy. The Soviets saw this as interference in their internal affairs and began to view détente with suspicion.
Strategic Arms Limitation Talks (SALT II)
Negotiations continued with the goal of extending arms control through SALT II. Although an agreement was signed in 1979, it was never ratified by the U.S. Senate. Growing mistrust, along with concerns over Soviet compliance and military buildup, led to political resistance in Washington. SALT II became a symbol of détente’s limitations.
Expansion of Soviet Influence
Throughout the 1970s, the Soviet Union expanded its influence in the Third World, supporting Marxist movements in Africa, Asia, and Latin America. For example:
- Angola and Mozambique saw Soviet and Cuban involvement in revolutionary regimes.
- In Ethiopia, the Soviets backed a pro-communist government during a brutal civil war.
- In Nicaragua, the U.S. was alarmed by the rise of the Sandinistas, who had ties to the USSR.
These actions fueled fears in Washington that the Soviet Union was using détente as cover while expanding its ideological reach. American conservatives, led by figures such as Ronald Reagan, accused the Soviets of betraying the spirit of détente.
The Invasion of Afghanistan: The Final Blow
The event that most clearly marked the end of détente was the Soviet invasion of Afghanistan in December 1979. The USSR intervened to support a faltering communist government against insurgent forces. From the American perspective, this was a blatant act of aggression and expansion into a geopolitically strategic region.
U.S. Response to the Invasion
The invasion triggered a strong reaction from the Carter administration, which took several major steps:
- Withdrew SALT II from Senate ratification
- Imposed economic sanctions on the Soviet Union
- Ended grain exports to the USSR
- Led a boycott of the 1980 Summer Olympics in Moscow
- Increased U.S. military spending and aid to anti-Soviet forces in Afghanistan (including the Mujahideen)
The Soviet invasion not only ended any remaining goodwill between the superpowers, but it also reignited Cold War hostilities on multiple fronts.
Political Shifts in the United States
The 1980 election of Ronald Reagan marked a clear ideological shift in American foreign policy. Reagan, a staunch anti-communist, rejected the principles of détente. He believed the Soviet Union was an evil empire that should be confronted, not accommodated. His administration pursued a policy of military buildup, aggressive rhetoric, and support for anti-communist movements around the world.
Under Reagan, the U.S. accelerated the arms race, launching initiatives such as the Strategic Defense Initiative (SDI) and boosting funding for NATO forces in Europe. Détente was officially dead by the early 1980s, replaced by a new phase of confrontation and strategic competition.
European NATO Allies and the Deployment of Missiles
Another major point of tension came from NATO’s decision to deploy American nuclear missiles in Western Europe in response to Soviet SS-20 missiles. The so-called Euromissile Crisis led to massive protests across Europe and further deteriorated East-West relations.
The Role of Ideology and Domestic Politics
Ideology played a significant role in the collapse of détente. While détente was based on realism and mutual interest, both American and Soviet hardliners viewed cooperation as weakness. In the U.S., many conservatives believed the policy allowed the Soviet Union to grow stronger unchecked. In the USSR, leaders were suspicious of Western intentions and resistant to any reforms that could challenge Communist Party control.
Additionally, domestic political shifts in both countries affected the trajectory of foreign policy. In the U.S., political pressure from Congress and public opinion increasingly leaned against accommodation with the Soviets. In the USSR, Brezhnev’s aging leadership became less dynamic and more resistant to change, creating stagnation in policy and diplomacy.
Détente came to an end due to a combination of ideological divisions, strategic miscalculations, global conflicts, and internal political dynamics. The most definitive factor was the Soviet invasion of Afghanistan in 1979, which destroyed trust and led to a sharp reversal in U.S. foreign policy. Though détente had once offered hope for a more stable and cooperative international order, its collapse revealed the deep-rooted mistrust and rivalry between the superpowers. The end of détente ushered in a new and intense phase of the Cold War, one that would continue until the eventual dissolution of the Soviet Union in 1991.