John J. McCloy

John J. McCloy was a lawyer, government official, and influential postwar institutional figure whose interventions repeatedly tested how American power should be used and how security should be judged. He urged President Harry S. Truman to consider ending the war with Japan through political terms rather than rushing toward invasion or atomic attack; later, he opposed a punitive approach to international atomic control, and in 1954 he defended J. Robert Oppenheimer against the security case brought against him. Across these episodes, McCloy’s characteristic argument was that policy could not be reduced to displays of force or mechanical tests of loyalty: judgment, context, and the value of a person’s mind mattered.

Wartime Counsel and the Choice Over Japan

On May 28, 1945, while serving as assistant secretary of war, McCloy urged Henry L. Stimson to recommend dropping the demand for “unconditional surrender.” Intercepted Japanese communications suggested to McCloy and other officials that senior figures in Tokyo were seeking a way to end the war, provided Japan could retain its emperor and constitutional order. McCloy carried that assessment to Truman’s administration at a moment when decisions about invasion, Soviet involvement, and the atomic bomb were converging. His proposal did not treat the Japanese government’s condition as a guarantee of surrender; it treated it as a political opening worth testing before the United States chose its next military step.

On June 18, McCloy told Truman that Japan’s military position was so desperate that the need for Soviet help to defeat it was itself open to question. Before deciding either to invade the Japanese home islands or to use the atomic bomb, he urged the president to take political steps that might secure surrender. Japan should be told that it could retain the emperor and choose its own form of government. He also proposed warning that the United States possessed another, terrifyingly destructive weapon. The distinction was consequential: McCloy advocated making the weapon’s existence part of a warning intended to end the war, rather than assuming that its first use was inevitable.

Truman seemed receptive to these suggestions. By July 17, McCloy’s diary recorded his belief that a warning delivered at that moment could bring the successful termination of the war. The entry reveals his confidence in a diplomatic alternative, not proof that it would have worked. In the book’s account, his recommendation stands against the momentum toward military action: he thought timing and a credible warning might change the outcome before an invasion or atomic attack.

Atomic Control and a Dispute Over Punishment

After the war, McCloy became involved in the effort to devise international control of atomic energy. Dean Acheson and David Lilienthal worked to keep the Acheson-Lilienthal plan alive, and McCloy participated in the political deliberations over what form control should take. The dispute was not simply over whether the atomic danger was real. It concerned whether an agreement could be cooperative if the United States intended to preserve its atomic monopoly while imposing severe penalties on other states.

At a meeting arranged by Acheson at Blair House on May 17, 1946, McCloy and Acheson objected to placing punitive provisions at the center of the proposal. McCloy regarded the American position as incompatible with genuine international control: the United States was continuing to build and test atomic weapons, while the plan proposed conditions the Soviet Union was unlikely to accept. He rejected the premise that complete security could be guaranteed and called the proposed automatic penalties presumptuous. The disagreement exposed a conflict between two meanings of control—an arrangement for cooperation over nuclear energy, or a pact that would extend American advantage. Felix Frankfurter later described the meeting as a “real bullfight,” and reported that McCloy had been so disgusted with the other side that he sputtered “dust in the air.”

A Critical View of Truman and the Security Climate

McCloy’s judgments of Truman were unsparing but not simply dismissive. He described the president as “a simple man, prone to make up his mind quickly and decisively, perhaps too quickly—a thorough American.” He also characterized Truman as common and hearty-natured, but not distinguished or “Lincolnesque.” In McCloy’s view, Truman’s instincts in atomic diplomacy were insufficiently measured for the challenge the country and the world faced. This assessment links McCloy’s advice on Japan to his broader unease about decisions made too quickly in the new atomic era.

In the spring of 1946, J. Edgar Hoover’s FBI investigated McCloy along with other senior officials associated with atomic policy, questioning their loyalty on the basis of allegations attributed to informants. McCloy’s inclusion shows how suspicion reached beyond scientists and people with left-wing associations to officials near the center of government. The scrutiny forms a telling background to his later defense of Oppenheimer: McCloy had himself been among the officials whose loyalty Hoover questioned, though the evidence here does not establish that this experience caused his position in the hearing.

From Admiration to Advocacy for Oppenheimer

McCloy had met Oppenheimer during the war and remembered him as a man of wide culture, with an “almost musically delicate mind” and great charm. Leslie Groves thought Oppenheimer’s influence over people could be excessive, recalling that David Lilienthal became so deferential that he consulted Oppenheimer about what tie to wear. McCloy’s admiration was less a report of formal allegiance than a recognition of intellectual and personal force. It helps explain why the later case against Oppenheimer struck him as a question about the meaning of security, not merely an assessment of past associations.

By 1954 McCloy was chairman of Chase National Bank, a member of Dwight D. Eisenhower’s private kitchen cabinet, and chairman of the Council on Foreign Relations; he also served on the Ford Foundation board and the boards of several major corporations. He had continued to see Oppenheimer at the Council on Foreign Relations and, by his own account, had no serious doubts about his loyalty. When he read James Reston’s report on the case on April 13, he found it profoundly disturbing. He later recalled that he did not care whether Oppenheimer had been sleeping with a Communist mistress. The formulation stripped away the scandalous framing and insisted that private association, by itself, did not answer the question of public trust.

McCloy wrote Eisenhower that he was distressed by the case and compared investigating Oppenheimer’s security risk to investigating Newton or Galileo. Such people, he argued, were “themselves always ‘top secret.’” Eisenhower replied that he hoped the Gray Board would exonerate the distinguished scientist. McCloy then agreed, at the end of April, to appear as a last-minute defense witness after Lloyd K. Garrison persuaded him. His testimony challenged the board’s definition of security: rather than treating questionable background as an automatic disqualification, McCloy asked whether an employee’s exceptional knowledge could alter the balance of risk.

He made the argument concrete through a hypothetical employee who knew more about the intricacies of time locks than anyone else in the world. In such a case, McCloy said, he might hesitate before dismissing the person and would weigh the risks against the value of the expertise. He applied the same reasoning to Oppenheimer, saying, “I would accept a considerable amount of political immaturity in return for this rather esoteric, this rather indefinite, theoretical thinking that I believe we are going to be dependent on for the next generation.” The testimony did not deny the existence of political concerns; it argued that security required judgment about what a person could contribute, and what the country might lose by excluding him.

The Measure of McCloy’s Intervention

McCloy’s role in Oppenheimer’s hearing completes a pattern already visible in his wartime counsel and his arguments over international control. In each setting, he resisted a policy that treated force, punishment, or suspicion as self-validating. He had urged Truman to try a warning and revised terms before resorting to the most destructive options; he opposed atomic-control provisions that would preserve a U.S. monopoly under punitive conditions; and he challenged a hearing that, in his view, risked sacrificing exceptional theoretical intelligence to an expansive definition of political risk.

That consistency did not make his positions identical or guarantee that his alternatives would succeed. It did, however, give his defense of Oppenheimer a wider significance than personal admiration. McCloy argued that national security could be damaged as well as protected by official decisions: a country might weaken itself by discarding knowledge and judgment in the name of eliminating every uncertainty. His interventions left him as a recurrent critic of policies that confused severity with prudence.