Korean War Facts
The failure to hold free elections throughout the Korean Peninsula in 1948 deepened the division between the two sides; the North established a communist government, while the South established a capitalist one.
The 38th parallel increasingly became a political border between the two Korean states. Although reunification negotiations continued in the months preceding the war, tension intensified. Cross-border skirmishes and raids at the 38th Parallel persisted.
The situation escalated into open warfare when North Korean forces invaded South Korea on 25 June 1950.
It was the first significant armed conflict of the Cold War.In 1950 the Soviet Union boycotted the United Nations security council, in protest at representation of China by the Kuomintang / Republic of China government, which had taken refuge in Taiwan following defeat in the Chinese Civil War.
In the absence of a dissenting voice from the Soviet Union, who could have vetoed it, USA and other countries passed a security council resolution authorizing military intervention in Korea.