At dawn on Sunday, June 25, North Korean troops begin a full-scale invasion along large portions of the 38th parallel.

The attack begins with heavy artillery fire followed by waves of Soviet-built T-34 tanks and an overpowering assault by the North’s well-trained infantry. Outnumbered and ill-prepared, South Korean troops are no match and are forced to flee en masse.

North Korea claims that its attack came only after South Korean forces fired first. While there had been frequent border skirmishes, the size of the invasion made it clear that North Korea and its premier Kim Il Sung were preparing for months to wage war. The United Nations Security Council — meeting in an emergency session — unanimously condemns the invasion and calls for North Korea to withdraw.

The Soviet Union could have vetoed the UN resolution, but did not.  The Soviets had been boycotting the UN for its refusal to grant Communist China a permanent seat on the Security Council.

President Harry Truman and his top advisors meet to formulate a plan of action.  The President decides that U-S military involvement is a must.

Truman would later say, “Communism was acting in Korea, just as Hitler, Mussolini and the Japanese had 10, 15, and 20 years earlier. I felt certain that if South Korea was allowed to fall, Communist leaders would be emboldened to override nations closer to our own shores. If the Communists were permitted to force their way into the Republic of Korea without opposition from the free world, no small nation would have the courage to resist threat and aggression by stronger Communist neighbors.”