Franklin D. Roosevelt

Franklin D. Roosevelt occupies a consequential place in the book as a leader whose domestic reform had once inspired J. Robert Oppenheimer and whose death abruptly altered the setting in which the atomic bomb’s future would be debated. He appears through political allegiance, wartime argument, and posthumous remembrance: Oppenheimer’s faith in the New Deal survived political disappointments, but Roosevelt did not live to shape the postwar nuclear order that Oppenheimer hoped might grow from his example.

Roosevelt and Oppenheimer’s Political Allegiance

Roosevelt’s New Deal was more than a policy program to Oppenheimer; it was a political commitment that remained visible even as the physicist’s associations and views shifted. Friends regarded him as an ardent Roosevelt supporter. In the days before the 1940 presidential election, Oppenheimer lobbied Ernest Lawrence so vigorously for Roosevelt’s third term that Lawrence, who had been undecided, promised to vote for him. The episode shows Oppenheimer treating political persuasion as a matter of personal urgency, and Roosevelt as the candidate whose case he believed a friend needed to hear.

That attachment had developed against the background of the Depression and the widening political struggle in California. In 1930, three of every four California voters were registered Republicans; eight years later, Democrats outnumbered Republicans two to one. Upton Sinclair nearly won the governorship in 1934 on his End Poverty in California platform, while in 1938 the reformer Culbert L. Olson became governor with the open support of the state Communist Party, campaigning under a united-front slogan against fascism. These figures place Oppenheimer’s support for Roosevelt within a broader leftward movement, without making his politics identical to those of the people around him.

That distinction matters because an anonymous 1940 pamphlet associated by Haakon Chevalier with Oppenheimer sharply attacked Roosevelt. It condemned cuts to welfare relief alongside increased armaments spending and accused the administration of abandoning social reform, organized labor, and civil liberties. The pamphlet went so far as to call Roosevelt a reactionary and a warmonger. But the book treats Oppenheimer’s possible role cautiously: if he helped draft it, the polemic departed from his usual rational style, and his correspondence suggests disappointment with Roosevelt rather than a readiness to denounce him. His political record therefore holds both a radical critique of the administration’s turn and a strong personal allegiance to Roosevelt’s New Deal.

The Death and the Memorial

On Thursday afternoon, April 12, 1945, news of Roosevelt’s death spread through Los Alamos. Work stopped, and Oppenheimer summoned the community to the flagpole by the administrative building for a formal announcement. He arranged a memorial service for Sunday. A deep snowfall had covered the mesa by that morning; at the theater, Oppenheimer spoke quietly for two or three minutes, in words that Phil Morrison remembered as coming from Oppenheimer’s heart and from the assembled community’s.

Oppenheimer had prepared a short eulogy that presented Roosevelt as a source of moral and political direction during years of war. He called the preceding period one of great evil and terror, and described Roosevelt as, “in an old and unperverted sense, our leader.” Turning to the Bhagavad Gita, he recalled the teaching that a person is shaped by faith. Roosevelt, he said, had inspired millions to believe that the war’s sacrifices could lead to “a world more fit for human habitation.” The eulogy ended not with a claim that Roosevelt’s work was complete, but with a call to hope that “his good works will not have ended with his death.” The service gave public form to Oppenheimer’s grief while also expressing the political expectations he still attached to Roosevelt’s leadership.

Afterward, Oppenheimer voiced a hope that the president’s successors might continue a different kind of political work. He believed Roosevelt and his associates had learned from Niels Bohr that the new weapon demanded radical openness. His wry comparison was, “Roosevelt was a great architect, perhaps Truman will be a good carpenter.” The remark joined admiration for the dead president to uncertainty about Harry S. Truman: the successor might be able to build on a larger design, but Oppenheimer could not know whether he would do so.

A Postwar Atomic Question Left Open

Roosevelt’s death also closed off one possible route for raising doubts about the bomb’s use. Leo Szilard had first urged the creation of an atomic-weapons program, but by 1945 he was trying to prevent the weapons from being used against Japanese cities. He drafted a memorandum for Roosevelt, introduced by a letter from Albert Einstein, warning that an atomic-bomb demonstration could provoke an arms race with the Soviet Union. Roosevelt died before Szilard could meet him. Szilard then sought an appointment with Truman, while also writing to Oppenheimer that, without a policy to avoid an arms race, using the bomb against Japan might be unwise. Oppenheimer did not reply.

On May 31, less than seven weeks after Roosevelt’s death, Oppenheimer attended a meeting of Henry L. Stimson’s Interim Committee. The question of whether to use the bomb against Japan was not on the agenda; the choice was treated as effectively settled, and the scientists who had spent two years building the weapon had no decision-making role on its military use. Yet Stimson framed the bomb as a transformation reaching beyond the immediate war, one that might become a force destructive of its creators or might contribute to global peace. The meeting thus exposed the distance between the bomb’s immediate military path and the larger questions that Roosevelt’s death had left unresolved.

Oppenheimer carried Roosevelt’s hope for openness into discussion of relations with the Soviet Union. At the committee meeting, he argued against prejudging the Soviet attitude and favored the possibility of cooperation. George C. Marshall went further, suggesting that prominent Soviet scientists might be invited to witness the test. James F. Byrnes objected that such an invitation could lead Stalin to seek participation in the atomic project. Byrnes also pressed for rapid production and research to keep the United States ahead. Oppenheimer and the other scientists understood the contradiction: the bomb’s physics could not remain secret indefinitely, and racing to preserve superiority risked driving the Soviet Union into a nuclear competition. Roosevelt’s hoped-for openness had become a dispute among officials and advisers, not an established policy.

Roosevelt’s Posthumous Presence

In later recollections, Roosevelt remained a possible hinge between wartime leadership and a different postwar future. Oppenheimer told friends that he wanted someday to write a play exploring what might have happened had Roosevelt lived into the postwar period. The imagined play is evidence of a question rather than an answer: Roosevelt’s survival could be contemplated, but the book does not claim that it would have produced a particular policy or prevented an arms race.

The political value attributed to atomic power also outlasted Roosevelt. At Potsdam, Joseph E. Davies recorded James F. Byrnes referring to the “New Mexico situation” as a source of great power that would, in the final analysis, control. The remark belongs to the post-Roosevelt struggle over the bomb’s diplomatic meaning, and contrasts with Oppenheimer’s hope that the new weapon would lead to cooperation rather than coercive advantage. Roosevelt’s significance in the narrative rests partly in that contrast: the admiration he inspired, the unfinished political possibility attached to his death, and the postwar decisions made in his absence.