Truman, Congress, and Korea: The Politics of America's First Undeclared WarThree days after North Korean premier Kim Il Sung launched a massive military invasion of South Korea on June 24, 1950, President Harry S. Truman responded, dispatching air and naval support to South Korea. Initially, Congress cheered his swift action; but, when China entered the war to aid North Korea, the president and many legislators became concerned that the conflict would escalate into another world war, and the United States agreed to a truce