Final answer:
The Korean War marked a turning point in the Cold War because the US used military force to stop the spread of communism.
Step-by-step explanation:
The Korean War marked a turning point in the Cold War because the US used military force to stop the spread of communism. The war began when North Korea invaded South Korea, prompting the United States and its allies to provide military support to South Korea. This was the first direct military confrontation between the US and the Soviet Union, who supported North Korea. The Korean War demonstrated the resolve of the US to contain the spread of communism and set a precedent for future conflicts during the Cold War.
Learn more about Korean War and its significance in the Cold War