Who gave his consent to the North Koreans to start the war?

Chinese leader, Mao Zedong sent troops to North Korea and warned the United States to keep away from the Yalu boundary unless it wanted an all-out war. The Chinese were worried about the American troops crossing the border between North Korea and China, which was the Yalu River. They began to be concerned about the attack on Chinese territory. The war was provoked by the unstable dictatorships that were at odds about boundary issues.

The battle was against the bon-dage that communism enforced. General MacArthur was very much in favor of the war, while President Truman was hesitant, but later agreed to MacArthur’s viewpoint, only after firing the General for insubordination. There documentation that suggests that Stalin instigated the war so that the US would become involved and not be able to defend South Korea.