June 25 marks the day in 1950 when North Korean forces crossed the 38th parallel into South Korea, sparking the 3-year Korean War.
After Japan was defeated in World War II, Korea (which had been occupied by Japan) was divided between the Soviet and the U.S. occupying forces, with the 38th parallel acting as boundary between the two spheres of influence. But despite the distinct demarcation between the two halves that existed in Western minds, both the communist government in northern Pyongyang and the democratic government in southern Seoul considered themselves leaders of the entire country. The two sides squabbled and tried to provoke attacks, until finally North Korea invaded the South.
Western leaders, especially President Truman, worried that not intervening in the Korean situation would mean the spread of communism worldwide. The United Nations Security Council met and agreed to send troops; the Soviet Union, who could have provided the dissenting vote, boycotted the meeting to protest the lack of representation for the People’s Republic of China.
At first Truman, while not hesitant to intervene in Korea, was concerned that if the Soviet Union got actively involved on the side of the North Koreans, it could start another World War, so he committed only air and naval forces. But when the Soviet Union hinted that they didn’t intend on sending troops to Korea, the United States sent ground troops to aid the South. The United States ultimately sent 302,000 troops to join the 42,000 UN and 600,000 South Korean forces. Meanwhile, the North’s army of 260,000 was ultimately bolstered by 926,000 Chinese and 26,000 Soviet troops.
The active fighting of the Korean War lasted until July 27, 1953, when, with hundreds of thousands killed on both sides and the fighting at a stalemate, an armistice agreeing to a cease-fire was signed. The Demilitarized Zone (DMZ) was established between the two countries at the 38th parallel. Because no peace treaty was ever signed, the war is technically ongoing, but most consider the conflict to be over.