Question

question 22 - multiple choice
in korea the government forces, which were armed to prevent border raids and to preserve internal security, were attacked by invading forces from north korea
the attack upon korea makes it plain beyond all doubt that communism has passed beyond the use of subversion to conquer independent nations and will now use armed invasion and war. it has defied the orders of the security council of the united nations issued to preserve international peace and security
statement on the situation in korea by president harry s. truman, june 27, 1950
courtesy of the american presidency project
based on the text, what caused the united states to become involved in the korean war?

communist forces in north korea had become more aggressive.

south korea had agreed to accept a communist form of government.

cooperation with russian forces against north korean forces had failed.

north korean forces had developed the capability to strike the united states.

Explanation:

The text states that North Korean invading forces attacked South Korea's government forces, and Truman's statement links this aggression to communism's use of subversion/armed invasion. The other options contradict the text: South Korea did not accept communism, there’s no mention of failed Russian cooperation, and North Korea lacked U.S.-strike capability then.

Answer:

Communist forces in North Korea had become more aggressive.