Kim wanted reunification under his rule. Soviet backing and expectations of Chinese help made an attack seem possible, while uncertain American commitments encouraged a risky calculation.
In 1949, Mao Zedong's communists won control of mainland China and established the People's Republic of China (PRC). North Korea now had a large communist neighbour. Korean soldiers who had fought in China returned with combat experience. In February 1950, China and the USSR signed the Sino-Soviet treaty: Sino-Soviet means between China and the Soviet Union. The alliance strengthened the appearance of a united communist group, although each leader had his own interests.
Kim repeatedly asked Soviet leader Joseph Stalin to support an invasion. Stalin had feared a war with the USA, but in 1950 approved preparations on condition that Kim also secured Mao's agreement. Soviet weapons and assistance helped the North prepare a large attack. Meanwhile, most American combat troops had left South Korea, and public American statements did not clearly promise to defend it. Kim and his backers hoped for quick success without American intervention. That was a judgement about the risk, not an American promise to stay out.
Worked example: Ambition, support and a risky expectation
Explain Soviet influence without treating Kim as a leader with no aims of his own.
- Kim supplied the aim: he wanted to unite Korea under his government and pressed for support to attack.
- Stalin's approval and Soviet weapons gave the plan resources it needed; Mao's agreement provided further backing.
- The hope that the USA would not intervene made the risk seem more acceptable. American intervention then showed why that expectation mattered and how badly it could fail.
Watch out for this
Soviet support means the invasion was simply Stalin's plan and Kim had no independent aim.
Kim wanted reunification and repeatedly sought backing. Soviet approval and weapons enabled his plan, so explain both the local ambition and the outside support.
Check your understanding
Which explanation best connects Kim's aim with the conditions for an invasion?
- His desire for reunification combined with Soviet backing and the belief that the USA might not intervene.
- China's communist victory removed the need for Soviet approval and weapons.
- The withdrawal of most American combat troops established a binding American promise to stay out.