The Korean War
The Korean War provided the first confrontation between two nuclear powers. And as the war progressed the conflict demonstrated how difficult it would be for either side to use atomic bombs decisively in battle.
The war broke out on June 25, 1950 when North Korean troops crossed the 38th parallel, invading South Korea. North Korean leader Kim Il-sung launched the attack once he had received a promise of support from Soviet leader Joseph Stalin. In January 1950, U.S. Secretary of State Dean Acheson haddelivered a speech in which he said South Korea and Taiwan were not part of the American "defensive perimeter," which seemed to indicate the U.S. would keep out of a Korean conflict. And it's clear that Stalin only agreed to support the invasion after being convinced the U.S. would not get involved.
However, Acheson's comments were misleading. The United States reacted to the news of the invasion by immediately taking steps to convene the United Nations Security Council. On June 27th the Security Council asked UN members to provide military assistance to help South Korea repel the invasion. U.S. forces went in on June 30th, by which time the North Koreans had taken the South Korean capital of Seoul. On September 15th, a UN force landed at Inchon and by September 29th, the UN troops had returned Seoul to the South Korean President. But by the end of the year the Chinese had intervened on behalf of the North Koreans halting the UN advance.
While the U.S. Strategic Air Command was well prepared to launch an all-out attack against the Soviet Union, it was less clear how it could use atomic weapons in a limited conflict like Korea. On August 1, 1950, the "decision was made to send the 9th Bomb Wing to Guam as an atomic task force immediately." Ten B-29s, loaded with unarmed atomic bombs, set out for the Pacific. On August 5, one of the planes crashed during take off from Fairfield-Suisun Air Force base near San Francisco, killing a dozen people and scattering the mildly radioactive uranium of the bomb's tamper around the airfield. The other planes reached Guam where they went on standby duty.
At a press conference on November 30, President Truman confirmed that he had been actively considering using atomic bombs in Korea since the beginning of the war. The comments provoked worldwide reaction and British Prime Minister Clement Attlee rushed to Washington to express his concern. Truman reluctantly reassured him that the U.S. had "no intention" of using atomic weapons in Korea except to prevent a "major military disaster."
So while President Truman tried to use his atomic superiority to the United States' advantage in North Korea he was never able to. Ultimately, it was not even clear that atomic bombing in a war against peasant armies would produce decisive results. If the Americans used the bomb and the Chinese forces kept on coming, it would demonstrate the bomb's ineffectiveness and reduce its deterrent effect in other arenas.
The war ended up being a see-saw affair that saw the UN forces retreat from North Korea to the Pusan perimeter in southeastern Korean and then forge forward again across the 38th parallel only to be driven south once more by the Chinese forces. In July 1951 after 13 months of fighting the two sides began armistice talks, which dragged on for more than two years. After Stalin's death in March 1953, the new leadership in Moscow moved more rapidly towards reaching an agreement. The cease-fire was ultimately signed on July 27, 1953.
The human cost of the war was catastrophic. In the first month of their operation alone, the Strategic Air Command groups dropped 4,000 tons of bombs. Besides high explosives, the bombers used napalm. In retirement, Curtis LeMay described the devastation saying, "we eventually burned down every town in North Korea... and some in South Korea too. We even burned down [the South Korean city of] Pusan -- an accident, but we burned it down anyway." Estimates of the casualties vary widely, but there is reason to believe that besides the three and a half million military dead, wounded and missing on both sides, more than two million civilians died in North Korea. In the end the border dividing the two countries remained exactly where it had been before the North Korean invasion.