INTRODUCTION
WHAT HAPPENED AT POTSDAM

It was not supposed to happen this way. Somebody had to tell him, and soon, before anything was .nal. He was going to be suspicious. He might ask questions, questions that could not or should not be answered. And what should he be told, anyway? The important thing was to make him think he knew everything, without actually letting him know anything important. Time was running out.
The path to Cecilienhof Palace runs through a picturesque garden alongside the lakes of Potsdam. Calling it a palace might be a tad grandiose. It was built as the residence of Crown Prince Wilhelm just before World War I, and it looks like nothing so much as a bloated Tudor country home somewhere in East Anglia. It would be a lovely place for a casual meeting among friends, except this was no casual meeting, and there were no friends here.
In July 1945, this picturesque garden happened to be located in the Soviet sector of occupation a few miles to the southwest of the smoldering rubble that had been the capital of Adolf Hitler's Third Reich. Here, in the suburbs of Berlin, American President Harry S. Truman arrived with his diplomatic and military entourage for a meeting, code- named Terminal, with the heads of state of the United Kingdom and the Soviet Union. Only .ve months had passed since their previous meeting at Yalta, yet the cast of characters had changed almost as completely as the setting. Winston Churchill had been defeated in the elections earlier that month by Labour Party leader Clement Attlee, and the Tory came along more as an honored guest and adviser than as one of the Big Three. Franklin Delano Roosevelt had died on April 12 and was succeeded by Truman, former Missouri senator and onetime haberdashery salesman who, like Attlee, did not have the bene.t of knowing what had happened, exactly, at Yalta. Only Joseph Stalin stood as a .xed point of this .nal postwar meeting. He was once again the host.
The Big Three had a great deal to discuss at Potsdam, but the issues clustered around one major and one minor axis: negotiating the postwar settlement in Europe and orchestrating the entry of the Soviet Union into the Anglo- American war with Japan. (Stalin had abrogated his neutrality pact with Japan in April but had not yet initiated hostilities in Asia.) Most of the discussions—often heated—concerned the former set of questions: What to do with Poland? Were there to be reparations, and if so, how much? How was an occupied Germany to be governed? An occupied Austria? All of these issues were contentious, and the faint .ssures that would crack into the chasms of the cold war began to snake across the surface of the wartime alliance.1
The minor axis was touchier, because Truman and his new secretary of state, James F. Byrnes, were not positive they needed Soviet entry to conclude the war against Japan. If it could be avoided, they certainly did not want it; dealing with the Soviets in Europe was bad enough. Military advisers to Truman still called for Soviet entry, and the sooner the better: Pinning down Japanese land forces in China and Manchuria would be dif.cult without the Red Army, and every bit of force was welcome. But Truman and Byrnes at times thought they could do without the Soviets, for they had something else, something new, something that might permanently give the West an edge over the Communists—not to mention over Emperor Hirohito.2
On July 16, a day before Terminal began, scientists working for the Manhattan Project had detonated the world's .rst atomic explosion in the desert outside Alamogordo, New Mexico: Operation Trinity. Atop a hundred- foot- tall tower, pieces of plutonium (a heavy metal generated from enriched uranium in atomic reactors—themselves new inventions), carefully machined and sculpted into segments of a sphere, were imploded into a dense core, which then began to .ssion. The heavy nuclei in the centers of the plutonium atoms split apart, releasing enormous amounts of energy. This physical process was discovered only in December 1938; plutonium was .rst secretly synthesized as recently as the winter of 1940–1941, and now the Americans held a deliverable weapon. The test had gone perfectly, and the Fat Man bomb, and a simpler uranium 235 gun model, code- named Little Boy, were being shipped off to the Paci.c to be detonated over specially selected Japanese cities. Perhaps the Soviets were not needed after all.
But still, Stalin needed to be told. Of.cially, he was an ally, although neither party trusted the other, and technically he was not yet an ally in the Paci.c war. Many of the American attendees harbored a growing feeling that Roosevelt's wartime alliance with Stalin either had been a mistake or was about to become one. Perhaps this was one area where the tendency to get too cozy with the Soviets could be checked. The Manhattan Project, begun as an Anglo- American collaboration, had deliberately and explicitly excluded the Soviet Union from the beginning.3 As far as Truman and Byrnes knew, Stalin remained completely ignorant of their determined efforts to weaponize uranium and plutonium—but he would certainly know once the .rst city was destroyed in early August, and he would know he had been left in the dark on purpose. Byrnes's initial impulse was to leave him there.
Secretary of War Henry L. Stimson disagreed. Stimson was an aged and dedicated Roosevelt appointee and onetime secretary of state under Republican President Herbert Hoover. (Stimson remained an adamant Republican under the two Democratic presidents he served.) Byrnes, not wanting the interference, made a point of not inviting him to the Potsdam meeting, but Stimson came anyway, mostly to advise Truman about S- 1 (his code name for the Manhattan Project). The time for stalling Stalin was over. The minutes of the recent meeting of the Anglo- American Combined Policy Committee on July 4, 1945, record that the secretary of war was already convinced that Potsdam was the place to lift the veil for the Soviets, at least a little:
If nothing was said at this meeting about the T.A. [tube alloys = atomic] weapon, its subsequent early use might have a serious effect on the relations of frankness between the three great allies. [Stimson] had therefore advised the President to watch the atmosphere at the [Potsdam] meeting. If mutual frankness on other questions was found to be real and satisfactory, then the President might say that work was being done on the development of atomic .ssion for war purposes; that good progress had been made; and that an attempt to use a weapon would be made shortly, though it was not certain that it would succeed.4
The Interim Committee—a group of civilian and military of.cials lightly peppered with scientists that Stimson had convened to discuss the wartime and postwar implications of the atomic bomb— had earlier "unanimously agreed that there would be considerable advantage, if suitable opportunity arose, in having the President advise the Russians that we were working on this weapon with every prospect of success and that we expected to use it against Japan."5 At .rst, Truman was hostile to the idea of informing Stalin, and
Winston Churchill was equally resistant. But the news of Trinity changed everything—for them and for Byrnes. Stimson recorded in his diary that Churchill "now not only was not worried about giving the Russians information of the matter but was rather inclined to use it as an argument in our favor in the negotiations." He continued: "The sentiment . . . was unanimous in thinking that it was advisable to tell the Russians at least that we were working on that subject and intended to use it if and when it was successfully .nished."6
On July 24 around 7:30 p.m., after a hard day of negotiations on European issues, Truman sauntered over to Stalin during a pause in the discussions, leaving his interpreter behind, and exchanged a few words. We will never know exactly what he said, or exactly what Stalin answered. The exchange would have enormous repercussions, but Truman, Stalin, and the latter's interpreter, V. N. Pavlov, have left no immediate transcript of what happened. Truman's interpreter, Charles "Chip" Bohlen, stayed back as his boss made his move:
Explaining that he wanted to be as informal and casual as possible, Truman said during a break in the proceedings that he would stroll over to Stalin and nonchalantly inform him. He instructed me not to accompany him, as I ordinarily did, because he did not want to indicate that there was anything particularly momentous about the development. So it was Pavlov, the Russian interpreter, who translated Truman's words to Stalin. I did not hear the conversation, although Truman and Byrnes both reported that I was there . . . Across the room, I watched Stalin's face carefully as the President broke the news. So offhand was Stalin's response that there was some question in my mind whether the President's message had got through. I should have known better than to underrate the dictator.7
Bohlen was not the only one who thought there might have been a miscommunication. Everyone in the know—Bohlen, Stimson, Byrnes, Churchill—watched the conversation carefully, although not too carefully, for they did not want to tip off Stalin that the exchange was important. As Byrnes recalled in his 1947 memoirs:
He [Truman] said he had told Stalin that, after long experimentation, we had developed a new bomb far more destructive than any other known bomb, and that we planned to use it very soon unless Japan surrendered. Stalin's only reply was to say that he was glad to hear of the bomb and he hoped we would use it. I was surprised at Stalin's lack of interest. I concluded that he had not grasped the importance of the discovery. I thought that the following day he would ask for more information about it. He did not. Later I concluded that, because the Russians kept secret their developments in military weapons, they thought it improper to ask about ours.8
By 1958, in his second set of memoirs, he had slightly revised his view:
I did not believe Stalin grasped the full import of the President's statement, and thought that on the next day there would be some inquiry about this "new and powerful weapon," but I was mistaken. I thought then and even now believe that Stalin did not appreciate the importance of the information that had been given him; but there are others who believe that in the light of later information about the Soviets' intelligence service in this country, he was already aware of the New Mexico test, and that this accounted for his apparent indifference.9
The Soviet dictator did not leave his own account of the exchange, but some in his delegation did. It is hard to take Soviet Foreign Minister V. M. Molotov's memoirs as completely reliable, for he recalled something that no one else in the room managed to observe—his own presence at the conversation—yet it seems certain that Stalin informed him about it immediately after. Here is Molotov's account: "Truman took Stalin and me aside with a secretive look and told us they had a special weapon that had never existed before, a very extraordinary weapon . . . It's hard to say what he himself thought, but it seemed to me he wanted to shock us. Stalin reacted very calmly, so Truman thought he didn't understand. Truman didn't say ‘an atomic bomb,' but we got the point at once."10 There are three important features about this Soviet version: Truman never speci.cally mentioned the nuclear character of the weapon; the Soviets knew what was actually behind his words, although they did not reveal it; and Stalin and his entourage saw this as a veiled threat. Marshal Georgii Zhukov, the commander of the Red Army and thus a crucial .gure at Potsdam, believed that Truman had gone up to Stalin "obviously with the goal of political blackmail," but noted that Stalin "didn't give away any of his feelings, acting as if he found nothing important in H. Truman's words."11
Which leaves us with the important question: What did Stalin think? What, in fact, did he really know about the atomic bomb before Truman's comment? Truman was certain that he knew nothing. As he stated in an interview in 1959: "When [New York Times journalist William Laurence] says that Stalin knew, he did not. He knew nothing whatever about it until it happened . . . He knew no more about it than the man in the moon."12 Yet, as is now abundantly clear in evidence from the Soviet archives, Truman misjudged his opponent. Stalin knew quite a lot. On August 7, the day after the destruction of Hiroshima by the Little Boy uranium bomb, Molotov (now back in Moscow) met with U.S. Ambassador Averell Harriman. He told the American: "You Americans can keep a secret when you want to."13 Harriman observed "something like a smirk" on Molotov's face, and later noted that "the way he put it convinced me that it was no secret at all . . . The only element of surprise, I suppose, was the fact that the Alamogordo test had been successful. But Stalin, unfortunately, must have known that we were very close to the point of staging our .rst test explosion."14
Harriman's intuition was correct. Zhukov noted that Stalin took Molotov aside that evening of Truman's casual conversation and said, "We need to discuss with Kurchatov the acceleration of our work."15 Igor Kurchatov was the scienti.c director of the Soviet atomic bomb project. Stalin not only knew about the bomb, he was building his own; Truman had not only failed to forestall Soviet proliferation, it appears he had accelerated it.
We now know that Stalin had authorized a Soviet atomic project much earlier, although it was still far from achieving a working nuclear device. Years away, in fact. Vladimir Merkulov—a commissar of the NKGB, the foreign intelligence branch of the People's Commissariat of Internal Affairs (NKVD) and thus under the direct command of Lavrentii Beria, Stalin's secret police chief and also overall director of the Soviet atomic project—reported immediately after the Yalta conference: "No time- frame of any certainty is available for the production of the .rst bomb, since research or design work has not been completed. It is suggested that the production of such a bomb will require one year at least and .ve years at most."16 Meanwhile, Stalin had to act calm. It would not do to show the Americans that he was concerned about the atomic bomb or about the fact that the Americans were the sole possessors of this new weapon. In an often- quoted September 17, 1946, interview with Sunday Times correspondent Alexander Werth, Stalin dismissed the notion of atomic blackmail:
I do not consider the atomic bomb as serious a force as certain political actors are inclined to consider it. Atomic bombs are designed to frighten the weak of nerves, but they cannot decide the fate of a war, since there is a completely insuf.cient number of atomic bombs for this. Of course, monopolistic possession of the secret of the atomic bomb creates a threat, but against that there exist, at least, two remedies: a) monopolistic possession of the atomic bomb cannot continue for a long time; b) the use of the atomic bomb will be banned.17
This playing down of the bomb became the standard strategy of Soviet diplomacy during the American atomic monopoly, and we can see its origins in that very exchange between Truman and Stalin at Cecilienhof Palace. Stalin remained poker-faced, indicating that nothing terribly new had happened, nothing to get upset about. This was an eminently sensible approach to handling an East- West confrontation that looked as though it was going to get worse.18 (Privately, Stalin may have felt more strongly. His daughter Svetlana reported that her father turned silent on hearing the news of Hiroshima, sullenly withdrawing to his chambers, at which point he became ill.19)
The day after Truman's conversation with Stalin, on July 25, the initiation of atomic bombing was authorized, and on the 26th the United States and United Kingdom—but without the Soviet Union, which was not yet a belligerent in the Paci.c war—issued the so- called Potsdam Proclamation, which threatened Japan with "prompt and utter destruction" if it did not unconditionally surrender immediately. Here Truman also did not explicitly mention the atomic bomb. Only on August 6, 1945, would the world understand what he had meant.20
Truman was by that date in the middle of the Atlantic on the USS Augusta. He had left Germany immediately after the conclusion of the conference on August 1—"I don't want to have to answer any questions from Stalin," he told an aide.21 And he would never have to. In a press conference on May 27, 1948, he informed America that "I have never had any communication from Mr. Stalin since Potsdam."22 Yet this should not lead us to believe that the conversation had been meaningless. The awkwardness of the way Truman .rst broached the topic of nuclear weapons between the two superpowers gave Stalin an excellent pretext to change his policy of cooperation with the West, and in the meantime inclined Truman to dig in his heels about any further revelations on the atomic front. J. Robert Oppenheimer, the scienti.c director of the atomic- bomb- designing laboratory of Los Alamos, thought that the failure to be absolutely clear and open had already soured any potential for cooperation with the Soviets regarding the international control of nuclear weapons, and somewhat melodramatically told Secretary of Commerce Henry Wallace that "the mishandling of the situation at Potsdam has prepared the way for the eventual slaughter of tens of millions or perhaps hundreds of millions of innocent people."23 We now know that the global nuclear holocaust did not happen, but Oppenheimer's worries that secrecy would breed animosity and then overt aggression seemed real enough at the time. The most important implication of Pots-dam, however, may have been in what Truman did not say: the words "atomic bomb." Given that Stalin already knew about the Manhattan Project and American plans to use it against Japan, the roundabout and vague way Truman went about "informing" the Soviet Union of his plans spoke volumes. As the historian Tsuyoshi Hasegawa perceptively put it: "To Stalin, the most important revelation was that Truman was withholding information about the atomic bomb."24 By trying to be oblique, Truman turned out to be too clever by half. It was not supposed to happen this way.

Excerpted from Red Cloud at Dawn : Truman, Stalin, and the end of the atomic monopoly by Michael D. Gordin.
Copyright © 2009 by Michael D. Gordin.
Published in 2009 by Farrar, Straus and Giroux.
All rights reserved. This work is protected under copyright laws and reproduction
is strictly prohibited. Permission to reproduce the material in any manner or
medium must be secured from the Publisher.