The Truman Administration was immediately informed of the invasion. Hesitant to get involved unless South Korea could not defend itself, the President decided to assist when the Republic of South Korea asked for America’s help. By the 26th of June, General MacArthur received new orders from the commander in chief and on June 30 was authorized to send in combat troops.
Truman advised the American public of his intention to intervene on June 27. (Later, he said it was the toughest decision he ever made in his life; for years he kept a letter from a bereaved father in his desk drawer.)
Although welcomed by South Korea, that military assistance was, at first, not as far-reaching as the Republic of Korea had hoped it would be. Nor was it without lingering controversy.
For starters, the US had no airbases in Korea. Air raids, at the beginning of the conflict, were often carrier-based. And when Americans were first placed in harm’s way, there was only one evacuation hospital and one Mobile Army Surgical Hospital (M*A*S*H) unit to support all American forces in Korea.
By September, however, the combined efforts of the U.S. and South Korean Armies, aided greatly by air and naval superiority, held the North Koreans in check at the Pusan Perimeter. On the 29th of September, 1950, Seoul was officially reestablished as the Republic of Korea’s capital city. By October, the North had sustained heavy equipment losses.
The conflict, however, was far from over.