Cold War ( 1979 – 85 ) The Cold War ( 1979 – 1985 ) refers to the phase of a deterioration in relations between the Soviet Union and the West arising from the Soviet invasion of Afghanistan in December 1979 . With the election of British Prime Minister Margaret Thatcher in 1979 , and United States President Ronald Reagan in 1980 , a corresponding change in Western foreign policy approach towards the Soviet Union was marked with the abandonment of Détente in favor of a more confrontational attitude towards the USSR in response to their war in Afghanistan . During this time the threat of nuclear war had reached new heights not seen since the Cuban Missile Crisis . In response to the 1979 Soviet invasion of Afghanistan , US President Jimmy Carter announced a US - led boycott of the Moscow 1980 Summer Olympics . In 1984 the Soviets responded with their own boycott of the 1984 Summer Olympics in Los Angeles , California . Tensions increased when the US announced they would deploy Pershing II missiles in West Germany , followed by US President Reagan ' s announcement of the US Strategic Defense Initiative . East and West tensions were further exacerbated in 1983 when Ronald Reagan branded the Soviet Union an " Evil empire " . In April 1983 the United States Navy conducted FleetEx ' 83 , the largest fleet exercise held to date in the North Pacific . The conglomeration of approximately forty ships with 23 , 000 crewmembers and 300 aircraft , was arguably the most powerful naval armada ever assembled . U . S . aircraft and ships attempted to provoke the Soviets into reacting , allowing U . S . Naval Intelligence to study Soviet radar characteristics , aircraft capabilities , and tactical maneuvers . On April 4 at least six U . S . Navy aircraft flew over one of the Kurile Islands , Zeleny Island , the largest of a set of islets called the Habomai Islands . The Soviets were outraged , and ordered a retaliatory overflight of U . S . Aleutian Islands . The Soviet Union also issued a formal diplomatic note of protest , which accused the United States of repeated penetrations of Soviet airspace . Also during 1983 , the civilian airliner Korean Air Lines Flight 007 was downed by Soviet fighter jets near Moneron Island . In November 1983 , NATO conducted a military exercise known as " Able Archer 83 " . The realistic simulation of a nuclear attack by NATO forces caused considerable alarm in the USSR , and is regarded by many historians to be the closest the world came to nuclear war since the Cuban missile crisis in 1962 . This period of the Cold War would continue through US President Reagan ' s first term ( 1981 – 1985 ) , through the death of Soviet leader Leonid Brezhnev in 1982 , the brief interim period of Soviet leadership consisting of Yuri Andropov ( 1982 – 1984 ) , and Konstantin Chernenko ( 1984 – 1985 ) . This phase in the Cold War concluded with the ascension of reform minded Soviet leader Mikhail Gorbachev in 1985 , who brought a commitment to reduce tensions between the East and West , and bring about major reforms in Soviet society . Soviet troops killed about one million civilians during the Soviet war in Afghanistan . Culture and media . Dozens of the board wargames were published covering both historical and hypothetical conflicts at scales ranging from man - to - man to global thermonuclear war . Historical conflicts include the Falklands War , the Iran – Iraq War , the invasion of Grenada , and the Angolan Civil War . The vast majority of titles concerned contemporary World War III " what - if " scenarios wherein the Cold War turns hot and focused on a presumed Warsaw Pact invasion of Western Europe . Notable games include " Ultimatum " ( 1979 ) , " The China War " ( 1979 ) , " NATO Division Commander " ( 1980 ) , " Fifth Corps " series ( 1980 ) , and " MechWar 2 " ( 1980 ) , " Task Force " ( 1981 ) , " Harpoon " ( 1983 ) , " Silo 14 " ( 1983 ) , " Assault " series ( 1983 ) , " Gulf Strike " ( 1983 ) , " Firepower " ( 1984 ) , " The Third World War " series ( 1984 ) , " Air Cav " ( 1985 ) and " Main Battle Area " ( 1985 ) . Two films released in 1983 , " WarGames " and " The Day After " , dealt with potential all - out nuclear war between the US and the Soviet Union . President Reagan was given a private screening of " The Day After " and was said to be deeply shaken . He revised his posture toward nuclear war in favor of eventual nuclear abolition , at least in part due to his experience watching the film .