Once Soviet intervention had been renounced, the people of Eastern Europe took matters into their own hands. Poland had assumed the lead, well before Gorbachev's time, under Lech Walesa and the Solidarity trade-union movement. Similar pro-democracy reform movements emerged in Czechoslovakia and throughout Eastern Europe. The movement climaxed in 1989 with the sudden dissolution of the Soviet empire. A leader of Solidarity became prime minister of Poland, where a year later the first free elections in sixty-eight years were held to turn out the communists. Soviet troops departed from Hungary, where a new government unearthed the remains of the martyred reform leader Imre Nagy, executed by the Soviets after the 1956 rebellion, in order to give him a burial ceremony with full honors. The poet and playwright Vaclav Havel led the "velvet revolution" in Czechoslovakia. In November 1989 security forces bludgeoned hundreds of protesters in Wenceslas Square in Prague, but even more massive crowds returned on successive days, shouting for an end to communism. The regime came tumbling down.
The most dramatic change came in Berlin, the heart of the nation that had been divided by the Cold War. After the East German authorities announced under pressure that citizens would no longer be prevented from traveling to the western sector of the city, the Berlin Wall, the ultimate symbol of the Cold War, literally crumbled in the hands of crowds of jubilant, hammer-wielding Germans. German reunification soon followed. Contending parties agreed on free elections in Albania and Bulgaria, but the regime of Nicolae Ceausescu in Romania grimly clung to power. In December, after his security police fired into crowds murdering hundreds of protesters, the Romanian army joined forces with the street protesters to topple the regime. Ceausescu and his wife were summarily executed by firing squad on Christmas Day 1989.
Meanwhile, in the Soviet Union itself, the three Baltic states of Estonia, Latvia, and Lithuania, forcibly annexed by Stalin in the 1939 pact with Hitler, demanded independence. All across the vast Eurasian empire, ethnic republics such as Azerbaijan, Belarus, Georgia, Moldavia, Tajikistan, Ukraine, and Uzbekistan rejected the essence of Soviet political life: the central authority of the Kremlin. Gorbachev repeatedly ruled out military intervention against the breakaway republics, but violence erupted in regions throughout the Soviet Union. Finally, in August 1991, on the eve of Gorbachev's planned signing of a new union treaty that would have created a formal confederation, hard-liners effected a coup, placing Gorbachev under house arrest in the Crimea. Protests, led by renegade Russian Communist Party leader Boris Yeltsin, overwhelmed the plotters of the coup after three days of tense standoff.
The collapse of the coup left a changed world in its wake. Gorbachev attempted to return to power after the coup, but in fact— because he was the leader of the discredited Communist Party—he had no real authority left. The Soviet reformer had won the Nobel Peace Prize but had lost the real prize: state power. Yeltsin assumed the Russian presidency under a new democratic system. Russia, and most of the fifteen other republics, rejected the Soviet system, though individual communists could remain engaged in parliamentary politics. The infamous KGB security police assumed a new name and no longer hounded intellectual critics of communism but otherwise remained active. Western Europe and the United States embraced the newly independent East European regimes, even encouraging several to join NATO over the opposition of Yeltsin and many residents of the former Soviet Union.
The United States confronted a world in which the nation's preeminent adversary for almost a half century had suddenly ceased to exist. President George H. W. Bush, who had succeeded Reagan in 1989, reacted cautiously to the dramatic change before declaring the triumph of the United States in the Cold War. The Cold War had been costly and dangerous but had provided a pernicious kind of stability in world affairs. With regional conflicts raging in the former Yugoslavia, Africa, parts of Asia, and in ethnic enclaves of Russia, many wondered if the post–Cold War world might bring even greater instability and uncertainty to world affairs.