In the 1950s and 1960s the United States was a vibrant society. Upward mobility was strong, and the middle class expanded. During the 1970s the internal contradiction in Keynesian demand management resulted in stagflation. Reagan’s supply-side economic policy cured that. With a sound economy under him, Reagan was able to pressure the Soviet government, which was unable to solve its economic problem, to negotiate the end of the cold war.