Multiple choice Why did the U.S. fight in the Korean war? To gain more territory To prove they had a strong military To stop the spread of communism To stop the spread of diseases Reveal answer Fill a bubble to check yourself C Correct answer Explanation The United States entered the Korean War in 1950 to defend South Korea from the invading communist North Korean forces. This action was aligned with the US policy of containment, which aimed to prevent the global spread of communism.