The Cold War ended much more suddenly than nearly anyone expected. In its aftermath historians have asked why it persisted as long as it did and why it ended so abruptly. The answer to the first is that both the United States and the Soviet Union promoted their conflicting visions of world order from the 1940s through the 1980s. They persisted in efforts to consolidate the American “empire of liberty” and the “empire of justice” during long periods of intense competition and briefer ones of détente or relation of tension.