How did decolonization and the end of the Cold War change Europe?

In the late 1960s and early 1970s the United States and the Soviet Union pursued a relaxation of Cold War tensions that became known as détente (day-TAHNT). The policy of détente reached its high point in 1975 when the United States, the Soviet Union, Canada, and all European nations (except Albania and Andorra) signed the Helsinki Accords. These nations agreed that Europe’s existing political frontiers could not be changed by force, and they guaranteed the human rights and political freedoms of their citizens. Détente stalled when Brezhnev’s Soviet Union invaded Afghanistan to save an unpopular Marxist regime. President Jimmy Carter reacted with alarm at the spread of Soviet influence, much like predecessors John F. Kennedy and Harry Truman.

Carter’s successor, Ronald Reagan (U.S. pres. 1981–1989), further re-ignited the Cold War by calling the Soviet Union the “evil empire” and deploying nuclear arms in western Europe. Reagan found conservative allies in British prime minister Margaret Thatcher and German chancellor Helmut Kohl. In the 1980s they gave indirect support to ongoing efforts to liberalize Communist eastern Europe. But as Reagan, Thatcher, and Kohl rekindled the Cold War, the Soviet Union underwent a cycle of reform that culminated in the release of Soviet control over eastern Europe and the dismantling of the Soviet Union and its Communist state.