Korea wasn’t just one war. After the North Koreans launched their surprise attack, the allies only controlled one major city, Pusan, and its surroundings in southeastern Korea, near Japan. MacArthur brilliantly counterattacked with an amphibious assault at Inchon to liberate Seoul, and then he swept north as the allies had reinforced South Korea. But then China sent hundreds of thousands of troops across the border, which MacArthur described as an entirely new war.

That second war, with China, almost became a nuclear war, as MacArthur supported using nukes tactically, including using nuclear waste to create an uncrossable border and against (presumably) military targets across the North Korean border in China. President Truman, who had authorized the bombings of Hiroshima & Nagasaki, at first seemed inclined to allow MacArthur to make those calls. Instead, he relieved MacArthur of command and fought the war to achieve a stalemate, which still holds in the armistice (under Eisenhower) and at the (heavily armed) ‘demilitarized zone’ between the two Koreas today.