Some unlikely people were responsible for ending the Cold War. Richard Nixon ushered in a period of détente with the Soviet Union and the opening of diplomatic relations with Communist China. Initially, Jimmy Carter built on this spirit of cooperation, only to see it end with renewed conflict with the Soviets. Finally, Ronald Reagan, a militant anti-Communist crusader, together with his pragmatic and steady secretary of state, George Shultz, guided the United States through a policy of heightened military preparedness to push the Soviet Union toward peace. It was a dangerous gambit, but it worked; diplomacy rather than armed conflict prevailed. Reagan’s Cold War strategy succeeded in part because during the 1980s a leader amenable to peace, Mikhail Gorbachev, governed the Soviet Union. He envisioned the end of the Cold War as a means of bringing political and economic reform to his beleaguered and bankrupt nation. What Gorbachev began, his successor, Boris Yeltsin, finished: the dismantling of the Soviet Union and its empire, and the infusion of democracy and capitalism into Russia.

The activism of ordinary people around the world also helped transform the relationship between the superpowers. Antinuclear protesters in Western Europe and the United States, including Barbara Deming and the Seneca Falls Women’s Encampment, kept up pressure on Western leaders to make continued nuclear expansion unacceptable. In Eastern Europe, Polish dockworker Lech Walesa and other fighters for democracy broke from the Soviet orbit and tore down the bricks and barbed-wire fences of the iron curtain.

The United States emerged as the winner of the Cold War, thereby gaining dominance as the world’s sole superpower. Yet this did not necessarily guarantee peace. In assuming this preeminent role, the United States faced new threats to international security from governments and insurgents seeking to rebuild nations along ethnic and religious lines in the Middle East and the Persian Gulf. Ironically, the bipolar Cold War in some ways had meant a more stable and manageable world presided over by the two superpowers. The collapse of the Soviet empire created a power vacuum that would be filled by a variety of unchecked and combustible local and regional forces intent on challenging the political and economic dominance of the United States.

At the same time, globalization presented new opportunities and posed additional challenges. It promoted more international cooperation and freer trade among nations. Globalization also fostered greater communication and cultural exchanges around the world. However, globalization brought many problems as well. Rapid industrialization and exploration of new sources of wealth accelerated the environmental dangers of air and water pollution, climate change, and the destruction of primeval forests. As globalization shrank the world economically and culturally, the United States became the chief target of those who wanted to contain the influence of Western values. Terrorism, which transcended national borders, replaced communism as the leading enemy of the United States and its allies.