Korea divided between North and South
After the Japanese surrender, the soviets remained obtaining the land of North Korea. At the same time, the US had troops in the south. This was when the 38th parallel was made in September 1945, which was the 38° N line to split the north and the south of Korea.
North Korea invades South Korea
On June 25, 1950, North Korea charged unexpectedly into South Korea, attacking their capital city of Seoul. This ends in a "bloody stalemate". The war was there, but this was the defining moment for the war.
MacArthur declares "There is no substitute for victory"
In March of 1951, Douglas MacArthur shows his frustration with the US for it's limited war against communism. This was in a message to House Republican leader Martin.
Truman relieves MacArthur of his command
On April 11th, 1951, Truman relieved MacArthur of his command. He did so because of several warnings he had heard about his insubordination. This caused an outrage in the people, because 69% of the population war for MacArthur.
Armistice formally re-established the division of Korea
In March of 1953, the line was re-established. Over 1,000,000 Koreans and 54,000 Americans were killed during this war. There was no formal peace treaty signed.