The world did! 36,000 Americans died trying. The UN, led by the US, fought a brutal war in Korea from 1950-53 that nearly liberated North Korea...until Mao's Chinese army crossed into North Korea in overwhelming numbers in a surprise attack that resulted in the current stalemate. It was a global effort, over 1,000 Brits also died and hundreds from many other random countries gave their lives trying to free North Korea.