Phase 1: UN Defense
The Korean War began with North Korea's attack on South Korea on June 25, 1950. This invasion was considered the first military action of the Cold War.6 Shortly thereafter the North Korean invasion, on June 27, President Truman issued a statement, declaring the U.S. commitment to support South Korea.6, 8,15 In the same letter, it is evident that the president believed the attack was "very obviously inspired by the Soviet Union," leading him to instantly conclude that Soviet Premier Joseph Stalin was involved in the invasion.8 By July 1, the U.S. had deployed its first ground combat troops and subsequently managed to defend Naktong, a provincial river in southeastern South Korea.6
On the other end of the line, it was apparently the North Korean leader, Kim II Sung, who wanted to unify Korea, and Stalin had actually refused this proposal several times.10 Yet, eventually, Stalin saw this as an opportunity to spread communism in Asia and to take pressure off the Soviet Union in Europe.10 Thus, Stalin agreed to help, but on the condition that China had to support the invasion. Mao Zedong, the leader of China, agreed with this because the country sought that they too, needed help from the Soviet Union.10, 19 Another to consider as a reason for Chinese involvement is that the US also intervened in the Chinese Civil War, so naturally, China wanted to do the same.2