The main concern of the U.S. during the Cold War was the containment of communism and the influence of the Soviet Union. The United States sought to prevent the spread of communist ideology, viewing it as a direct threat to democracy and capitalism. This led to various policies, including the Truman Doctrine, which aimed to support countries resisting communism, and the Marshall Plan, which sought to rebuild Europe to foster stable, capitalist democracies. The Cold War also resulted in military alliances, such as NATO, and numerous proxy wars or conflicts around the world, as the U.S. and the Soviet Union competed for global influence.