IB History Cold War Crises - the North Korean Invasion of South Korea Notes

The North Korean Invasion of South Korea (1950)

Division of Korea and Background to the Invasion

1. After Japan's defeat in 1945, Korea was divided along the 38th parallel - the USSR occupied the North and the USA occupied the South.
2. The division was intended to be temporary, but by 1948 two rival states had formed - the Republic of Korea (South) and the Democratic People's Republic of Korea (North).
3. Kim Il-sung led communist North Korea, while Syngman Rhee led the anti-communist South, both claiming authority over the entire peninsula.
4. Kim sought Stalin's approval to invade the South - Stalin agreed in early 1950, partly because the USA had excluded Korea from its defensive perimeter (Acheson Line).
5. Mao Zedong also supported the invasion, pledging Chinese backing - the communist victory in China in 1949 had shifted the regional balance of power.
6. Both superpowers built up their respective Korean allies with military equipment and advisors, making the peninsula a Cold War flashpoint by 1950.

The Invasion and UN Response (1950)

1. On 25 June 1950, North Korean forces crossed the 38th parallel with approximately 75,000 troops, rapidly pushing South Korean forces back.
2. Within days, North Korean forces captured the South Korean capital, Seoul, and by August had pushed defenders into a small area around Pusan.
3. President Truman saw the invasion as a test of containment - he feared that failure to act would encourage communist aggression elsewhere, as with appeasement in the 1930s.
4. The UN Security Council voted to authorise military action against North Korea - the USSR was absent, boycotting the Council over its refusal to seat communist China.
5. A UN force was assembled, dominated by US troops and commanded by General Douglas MacArthur.
6. This was the first time the United Nations had authorised military force to resist aggression - the Cold War had turned the Korean peninsula into a hot war.