The United States played a significant role in the Korean War, which occurred from 1950 to 1953. After North Korea invaded South Korea, the U.S. intervened under the auspices of the United Nations, leading a coalition to repel communist expansion. American military forces, driven by the policy of containment, aimed to prevent the spread of communism in Asia. The U.S. provided substantial ground troops, air support, and naval resources, contributing to key victories but also suffering heavy casualties. Ultimately, the war ended in a stalemate, leading to the continued division of Korea along the 38th parallel.