By December 1950 the US 8th army and the UN peacekeeping forces sent to South Korea were on the verge of reaching the Yalu river only to be pushed back into South Korea and eventually begin the 2-year stalemate and ending with the cease at the current border. So why how did the 8th army and the UN forces get pushed back so far so fast. They were facing a light infantry force reliant on human wave tactics (correct me if I'm wrong) that should have been slaughtered by allied fire support instead they fall back in the longest retreat in US history. The Question I'm asking is why how did the UN forces be forced to pull back when facing an enemy that by my accounts should have been stopped