When Mikhail Gorbachev became the leader of the Soviet Union in 1985, the USSR was one of the world's two superpowers. By 1989, his liberal policies of perestroika and glasnost had permanently transformed Soviet Communism, and had made enemies of radicals on the right and left. By 1990 he, more than anyone else, had ended the Cold War, and in 1991, after barely escaping from a coup attempt, he unintentionally presided over the collapse of the Soviet...