Why did the united states become involved in the korean conflict

The United States came to the aid of South Korea to repel the North Korean invasion.

Explanation:

The Korean War was carried out between 1950 and 1953. Its components were the Republic of Korea (or South Korea), supported by the armed forces of several countries commanded by the United States; and the Democratic People's Republic of Korea (or North Korea), supported by the People's Republic of China and the Soviet Union. The war was one of the early episodes of the Cold War. Ending more than 3 million civilians and almost 15% of the population of North Korea, it was one of the bloodiest wars in history.

Five years earlier, after the end of World War II, the United States and the Soviet Union agreed to divide Korea into two. They drew the border in parallel 38, leaving the North in charge of the Soviet Union and the South in charge of the United States. Each superpower controlled in its respective area the constitution of two new states that remained under their corresponding orbits: the Democratic People's Republic of Korea in the north and the Republic of Korea in the south.

Although negotiations were held for the reunification of Korea in the months before the war, tension intensified with cross-border skirmishes and incursions in parallel 38. The escalation of tension degenerated into an open war when North Korea invaded South Korea on June 25th, 1950.

The United States came to the aid of South Korea to repel the invasion. A rapid counteroffensive of US troops and other nations under UN mandate, returned North Korean troops north of the 38th parallel, almost to the Yalu River. Then the People's Republic of China entered the conflict on the North side, with arms support from the Soviet Union.