U.S.-Soviet relations refer to the diplomatic and political interactions between the United States and the Soviet Union during the 20th century, particularly during the Cold War. This period was marked by ideological conflict, with the U.S. promoting capitalism and democracy, while the Soviet Union supported communism. Tensions escalated through events like the Cuban Missile Crisis and the arms race. Despite these tensions, there were moments of cooperation, such as the Nuclear Non-Proliferation Treaty and various arms control agreements. The relationship began to thaw in the late 1980s, leading to the eventual dissolution of the Soviet Union in 1991, which significantly changed global dynamics.