Kennan learned of the Soviet test on September 13, two weeks after it had taken place. After receiving confirmation, Truman decided to make the news public, overriding Acheson’s initial inclination—which Kennan opposed—to let it leak out gradually: Stalin had as yet said nothing. The president’s announcement came on September 23. “Bedlam,” Kennan recorded in his diary that day, but on the next he noted that “for the most part, people took it calmly and the press did a good job of placing the event in the proper perspective.”6
Calm, however, was hard to maintain. Kennan had hoped for a continuation of wartime cooperation with the British and the Canadians in building atomic weapons: that was one of the reasons he wanted to keep them and the United States out of any Western European federation. But the Joint Congressional Committee on Atomic Energy had grown increasingly concerned about security, and now, in the wake of the Soviet test, Kennan concluded that international collaboration would have to end altogether, apart from a few agreements on the allocation of raw materials. Congressional fears, it turned out, were well founded. Donald Maclean, the British representative on the committee overseeing atomic bomb production, was a Soviet spy: thanks to him, Stalin knew more than Kennan did about the size of the American arsenal. Maclean’s treachery was not yet known in the fall of 1949, but the FBI did have evidence that Klaus Fuchs, a British scientist who worked on the Manhattan Project, had also leaked critical information to Moscow. That revelation explained to most people at the time—as it has to most historians since— how the U.S.S.R. got its own bomb so much sooner than anyone had expected.7
As it happened, Fuchs had also been present at a 1946 Los Alamos meeting during which the builders of the atomic bomb discussed the possibility of a thermonuclear, or hydrogen, or “super” bomb, based on the fusion of atoms instead of their fission, theoretically thousands of times more powerful than existing atomic weapons. Nothing had been done since to develop such a device, but when the news broke of the August 1949 Soviet atomic test, pressures began to mount, among the few scientists who knew that a “super” might be feasible, for the United States to build one. Who could say that a Soviet “super,” with Fuchs’s help, was not already under construction? Lewis L. Strauss, the most bellicose member of the Atomic Energy Commission, shared the scientists’ concerns, and on October 6 he conveyed them to Truman—for whom the concept of a hydrogen bomb was as unfamiliar as that of an atomic bomb had once been.8
It’s not clear when Kennan learned that thermonuclear weapons might be possible. But he met on October 12 with a group of Pentagon officers who favored greater reliance on atomic, biological, and chemical “weapons of mass destruction,” and the “super” was probably among the options discussed. What he heard, Kennan thought, reflected an overestimation of Soviet capabilities and a misunderstanding of Soviet intentions: “But I cannot prove this conviction, and the matters in question are too important for anyone to dare acting on a hunch.” By November 3, his position had become clearer. The United States, he told a Policy Planning Staff meeting attended by Acheson, was so far behind the Soviet Union in conventional military strength that its whole policy might soon be “tied to the atom bomb.” The question, then, was what the “super” bomb would accomplish.
Acheson acknowledged this, but then surprised Kennan, as he had done several months earlier on Program A, by thinking out loud. Could there be a two-year moratorium—“bilateral if possible, unilateral if necessary”—on the development of “super” bombs? Might that open possibilities for agreements on the international control of atomic weapons, on German and Japanese peace treaties, and maybe even on forgoing the use of “subversive tactics”? At least the Americans and the Soviets would be “attempting to do something constructive rather than just sitting and exchanging glassy stares.” If at the end of this “vacation” no progress had been made, then “go ahead with the overall production of both [atomic and thermonuclear weapons], backed up by your economy and your people, having made your best effort to do otherwise.”
This was, Acheson’s biographer has written, “a remarkable ball of wool” for him to have gathered, but the secretary of state’s mind was not normally woolly. His openness on this issue probably reflected his friendships with Oppenheimer and David E. Lilienthal, soon to retire as chairman of the Atomic Energy Commission. All three had worked, in 1946, on the imaginative Acheson-Lilienthal Plan for the international control of atomic energy: Truman had converted it, over their objections, into the more forbidding Baruch Plan, which the Soviet Union rejected. None now wanted a quantum leap in the lethality of weaponry when so little had been done, as yet, to limit the effects of the last one. Kennan liked what Acheson was suggesting, but Nitze did not, insisting that the burden of proof should fall on those who saw no power advantages in building the “super” bomb. He added tactfully, though, that the secretary of state’s question—whether “we would really be at a disadvantage if they developed it and we did not and why”—required further study.9
Kennan brought up Acheson’s idea of a “super” moratorium when he met with Oppenheimer in Princeton on November 16, only to have the physicist—still passionately opposed to developing such a weapon—throw cold water on it. However reasonable the plan might be, he wrote Kennan the next day, it would not seem so to those who demanded safeguards “of rigid and absolute quality.” Undaunted, Kennan on November 18 produced a draft presidential announcement that the United States would unilaterally forgo constructing thermonuclear weapons: they could serve no military purpose apart from mass destruction, they would add nothing to American security, and “for us to embark on such a path would certainly not deter others from doing likewise, and probably quite the contrary.”10
Truman, however, was not about to be rushed into any hasty decision. On the next day he ordered the formation of a special NSC committee, made up of Acheson, Lilienthal, and Secretary of Defense Johnson, to advise him on the matter. Since Johnson strongly supported the “super” and Lilienthal equally adamantly opposed it, Acheson’s would be the swing vote. To help him decide, he asked Kennan and Nitze to prepare separate reports on the matter, knowing that they would disagree. Acheson’s sympathies were with Kennan: his affectionate tribute at the National War College came only a few days after he read an early version of what Kennan was going to recommend. But Acheson’s political instincts told him that the decision would go the other way. For that reason, he put Nitze on the working group that advised the NSC committee.
Nitze’s report, completed on December 19, was short and to the point. Although fission weapons were likely to remain of primary importance in the military strategies of both the United States and the Soviet Union, there was at least a 50 percent chance that either country could achieve a thermonuclear reaction. Weapons of mass destruction—the hydrogen bomb apparently qualified, the atomic bomb did not—would serve American interests in neither peace nor war, and the Soviets would probably not initiate their use. Nevertheless, “it is essential that the U.S. not find itself in a position of technological inferiority in this field.” Accordingly, the president should authorize the Atomic Energy Commission to
Kennan, characteristically, wrote much more. He had begun composing a “super” bomb paper before Acheson asked him to, and he was determined to do justice to the secretary of state’s mandate. “Remarkable man,” Lilienthal noted, after watching Kennan read a draft: “Peeled off his coat, exhibiting farm-type gal-luses over his thin and bent shoulders. Then he nervously started rolling back his sleeves, folding them back by stages till they were way above his elbows.” Kennan submitted his final version, which came to seventy-nine pages, on January 20, 1950: he remembered it as “one of the most important, if not the most important, of all the documents I ever wrote in government.” Entitled “The International Control of Atomic Energy,” it called for nothing less than an end to reliance on nuclear weapons as instruments of offensive warfare.
Its reasoning echoed Henry Adams’s concern that morality was lagging behind technology. There was no way, Kennan argued, in which weapons of mass destruction could be made to serve rational ends beyond deterring the
