The US president, Harry S. Truman, dispatched US land, air, and sea forces to South Korea in support, hoping to drive the North Koreans back to their side of the 38th Parallel. As the US and South Korea pushed the North’s army back, communist Chinese forces intervened in late 1950.
By the middle of 1951, most major fights had ended. Both sides of Korea, both backed by large countries,were pushing from either side of the 38th parallel. The front lines stabilized, while negotiations began to be made. But this still wasn’t the end.