During World War II, the United States poured more than $2 billion dollars into the Manhattan Project, a crash program to build the world's first atomic bomb before Nazi Germany could acquire the deadly weapon. (Ironically the Germans abandoned their atomic project soon after the Americans began theirs, and the Americans' bomb was not ready for use until after Germany had surrendered. A weapon built to subdue Hitler would end up being dropped on Japan instead.) While the Manhattan Project employed more than 100,000 workers, the secret nature of the atomic program remained a tightly-guarded secret; many Manhattan Project employees did not even know the true purpose of their work. Knowledge of the program was restricted only to the atomic scientists themselves and to a handful of President Franklin D. Roosevelt's most trusted political allies. Even Vice President Harry Truman was kept in the dark. Roosevelt did share information about the atomic program with his close friend and ally, British Prime Minister Winston Churchill; in their correspondence the two leaders discussed the bomb under the codename, "Tube Alloys." As for the third of the "Big Three" Allied leaders, Soviet Premier Josef Stalin? Roosevelt and Churchill never told him about the bomb.
With the Manhattan Project such a closely guarded secret, the sudden detonation of the world's first atomic bomb over the Japanese city of Hiroshima in August 1945 truly shocked the world. Human ingenuity had found a way to weaponize the most elemental forces of nature, and humanity could never turn back. The nuclear age had begun.
At first, American leaders enjoyed the prospect of maintaining a nuclear monopoly, hoping that the threat of atomic attack would not only force Japan into an early surrender but also might help persuade the Soviets, America's uneasy wartime allies, to be more accommodating to American proposals for the postwar order. It's going too far to suggest, as some revisionist historians have done, that the United States dropped atomic bombs on Japan primarily in order to intimidate the Soviet Union. But if dropping the bomb had the side-effect of cowing the Soviets, American leaders surely wouldn't have complained.
American experts predicted that it would take other nations at least twenty years to develop their own atomic weapons, thus ensuring an American monopoly over the terrifying new technology for a full generation. The Soviets' successful detonation of a prototype bomb in 1949—just four years after Hiroshima—thus came as a terrible shock to the American people. Americans soon latched onto a scapegoat for the loss of their nuclear superiority: espionage. Investigations revealed that Soviet scientists had been helped in their pursuit of the bomb by information smuggled in from spies within American laboratories, and these discoveries gave rise to Red Scare and espionage hysteria in the United States. (Post-1991 revelations from Soviet archives suggest that espionage did not, in fact, provide much of a boost to the Soviet atomic program, mainly because the Soviets did not trust the information their spies sent over.) Some of the atomic spies—including the most famous, Klaus Fuchs—were Communists who chose to aid the Soviets for ideological reasons. Others were motivated less by a desire to strengthen Communism than by a conviction that no one nation—even the United States—could be trusted with sole and total control over such a powerful weapon. A young scientist named Theodore Hall gave the Soviets detailed information about the "Fat Man" bomb dropped on Nagasaki—which closely resembled the first bomb detonated by the Soviets in 1949—because he felt that "it was important that there should be no monopoly, which could turn one nation into a menace and turn it loose on the world... There seemed to be only one answer to what one should do. The right thing to do was to act to break the American monopoly."
The shock of the Soviet bomb spurred the United States to develop even more powerful bombs. Hoping to regain a nuclear advantage, in 1952 the Americans exploded the world's first hydrogen bomb, a much more powerful type of nuclear weapon that derived its power from fusion rather than fission. (Unlike fission, which releases energy by dividing an atom, fusion releases energy by bonding two smaller atoms together; fusion is what happens inside the sun.) Fusion creates a much more powerful explosion than fission; the Americans' first hydrogen bomb exploded with the force of 10.4 million tons of TNT, making it more than 100 times more powerful than the bombs that devastated Hiroshima and Nagasaki in 1945.
Scientists debated whether or not it was a good idea to work toward building such tremendous weapons. After the atomic bombing of Hiroshima and Nagasaki, Manhattan Project director J. Robert Oppenheimer told President Truman that the project's scientists had "blood on their hands." Oppenheimer was unsettled by Truman's joking response: "It'll all come out in the wash." By the early 1950s, Oppenheimer had become a prominent opponent of the development of the hydrogen bomb, advocating for international arms control as an alternative to the arms race then being waged by the United States and Soviet Union. Oppenheimer's dissent from Cold War orthodoxy made him a target for retaliation from foes within the scientific community, who cited Oppenheimer's past social contacts with left-wingers as grounds for revoking his security clearance. In 1953, the federal government's Atomic Energy Commission dug deep into Oppenheimer's past, catching the physicist in a series of evasions over past associations with Communists. In the end, the commission ruled Oppenheimer to be a national security risk and stripped him of his clearance to access classified information. J. Robert Oppenheimer, a man often called "the father of the atomic bomb," would no longer be able to enter the federal weapons laboratories he had helped to build. Oppenheimer's forced departure served as a warning to other scientists with qualms over the arms race, quieting opposition to the hydrogen bomb within the scientific community. Oppenheimer's status as the country's most prominent atomic physicist passed to Edward Teller, a man who had no doubts about the desirability of ever more powerful weaponry.
The development of more powerful nuclear warheads gave impetus to competing American and Soviet projects to create better unmanned technology—rockets and missiles—to deliver the new weapons. Atomic bombs like those used on Japan in 1945 were designed to be dropped by airplanes. But both the Americans and Soviets sought to replace manned bombers with Intercontinental Ballistic Missiles (ICBMs), which could travel through space at high speeds before reentering the atmosphere to rain down destruction on faraway targets. The development, on both sides, of ICBM technologies increased substantially the anxiety level of the nuclear era because the missiles not only made it easy to launch massive nuclear attacks in the heat of a crisis, but they also (unlike planes) could not be called back if launched erroneously. If a nuclear-armed ICBM were ever launched, worldwide destruction would be certain to follow.
As the number of nuclear weapons in Soviet and American arsenals rose and rose through the 1950s, both sides found themselves desperate to maintain nuclear parity with the other, yet simultaneously alarmed at the pace of the arms race and the growing possibility of nuclear holocaust. Edward Teller, the "father of the hydrogen bomb," later expressed regret at his role in the creation of those destructive nuclear weapons, which made the arms race into such an international obsession.
President Dwight Eisenhower's Secretary of State, John Foster Dulles, sought to use anxieties about nuclear weapons to his diplomatic advantage through his policy of "Massive Retaliation." In a 1954 speech, he said, "We want, for ourselves and the other free nations, a maximum deterrent at a bearable cost.... The way to deter aggression is for the free community to be willing and able to respond vigorously at places and with means of its own choosing." According to the policy of Massive Retaliation, the United States would respond to any attack against its allies not with conventional forces-as it had done in 1950 in Korea—but with "massive retaliation," a clear allusion to nuclear weapons. Thus a foray by Soviet allies against, say, Taiwan, might result in an American nuclear strike against the Soviet Union itself. Dulles believed that by threatening nuclear annihilation, he would deter attacks, making the actual use of nuclear weapons unnecessary. Thus the United States would use the atomic bomb as a tool for brinksmanship, threatening to unleash a worldwide nuclear holocaust as a means of deterring its enemies from undertaking more limited attacks against American interests. The bomb's true power would be found not in its use but in its capability to induce psychological terror.