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One of the more interesting inflection points in history is the disastrous attempt by Mao to intervene in the Korean War. The Chinese tried to night march and hide their forces from UN reconnaissance, but trying to march that many men in hiding simply wasn't possible and it was clear to UN forces by October 10th that China was going to invade and warned in no uncertain terms that any units crossing the Yalu would be dealt with with nuclear weapons due to their size.

The incident of course spooked both sides. It's only with hindsight that the UN realized that it was as much luck as inevitability that the Chinese were discovered before they crossed over into what was North Korea, and the Chinese realized that their massive human waves were useless if they were eviscerated before they even reached their enemy.

Of the two Communist Chinese leaders who most supported intervention, one would recover, one would not. Zhou Enlai regained a lot of respect in the party after forcing the US/UN to acknowledge the PRC and hammering out a 'favorable' solution for China regarding the Chinese/Korean DMZ* in the Camp David Accords of 1951. Mao, however, would not, and would die 'Falling down some stairs' shortly after Stalin bit it in 1953 and usher in Liu Shaoqi.

The Korean War is often one of the more forgotten wars simply because the Cold War was focused on the US vs the Soviets and not 'The Other Communists who weren't belligerent.' But what if we hadn't spotted the PVA intervention force before it was too late and they were overwhelming the frankly overextended UN forces? Or if Truman hadn't fired MacArthur on the spot for trying to goad the Chinese and force a nuclear response by moving beyond the freeze line of October 13th? How would world politics have evolved under a singular Containment policy of the US/NATO vs the Comintern as opposed to the carrot and stick approach of Containment or Engagement?

OOC: The DMZ is the top 70 km or so of what would be North Korea from the Chinese Border.
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