When was the Cold War?

The Cold War's chronology spans nearly half a century, though historians debate its precise beginning while generally agreeing on its end. The dating matters because it frames the longest sustained geopolitical rivalry in modern history.

The Cold War's origins can be traced to tensions that emerged even before World War II ended. The wartime conferences at Yalta and Potsdam (1945) revealed deepening disagreements between the Western Allies and the Soviet Union over the fate of postwar Europe. By 1946, George Kennan's 'Long Telegram' from Moscow articulated the case for containing Soviet expansion, and Winston Churchill warned of an 'Iron Curtain' descending across Europe. Most historians mark 1947 as the formal beginning, when the Truman Doctrine committed the United States to supporting nations threatened by communism and the Marshall Plan invested billions in Western European reconstruction.

The Cold War's major phases unfolded over four decades. The early period (1947–1962) saw the Berlin Blockade, the Korean War, the formation of NATO and the Warsaw Pact, the Hungarian uprising, and the Cuban Missile Crisis — the closest the superpowers came to nuclear war. The middle period (1962–1979) encompassed the Vietnam War, detente (a relaxation of tensions including arms control agreements), and growing Soviet influence in the Third World. The late period (1979–1991) began with the Soviet invasion of Afghanistan and Ronald Reagan's military buildup, continued through Gorbachev's reforms, and culminated in the revolutions of 1989 and the Soviet Union's dissolution.

Key dates punctuate the narrative: the Berlin Wall's construction (1961) and fall (1989), the Cuban Missile Crisis (1962), the Prague Spring's suppression (1968), Nixon's opening to China (1972), the Soviet invasion of Afghanistan (1979), and Gorbachev's rise to power (1985). Each marked a shift in the Cold War's dynamics.

The Cold War ended on December 26, 1991, when the Soviet Union formally dissolved. Gorbachev had resigned the previous day. The hammer-and-sickle flag was lowered from the Kremlin, replaced by the Russian tricolor. A conflict that had defined half a century of global politics — that had brought humanity to the brink of nuclear annihilation — ended not with a bang but with a bureaucratic act of dissolution.