Spying on the Nazi and Soviet Bombs

August 26, 2020

Editor’s Note: This is an excerpt from “Book Review Roundtable: Nuclear Spies” from our sister publication, the Texas National Security Review. Be sure to check out the full roundtable.

Vince Houghton, The Nuclear Spies: America’s Atomic Intelligence Operation against Hitler and Stalin (Ithaca, NY: Cornell University Press, 2019)


Since 2013, Chinese President Xi Jinping has repeatedly emphasized how important quantum computing will be in China’s future. Quantum technology, he declared in 2016, could bring about “a new industrial revolution.” Speaking on artificial intelligence, Russian President Vladimir Putin averred in 2017 that “the one who becomes the leader in this sphere will be the ruler of the world.” Unwilling to be left behind by its rivals, the United States has prioritized research in these cutting-edge fields as well. Military science and technological competition among the United States, Russia, and China in the foreground barely conceals a related intelligence competition being waged behind the scenes. Each side collects intelligence on its rivals’ scientists, universities, and laboratories, attempting to analyze their progress in order to shape research and policy. Uncertainty plagues this process, as participants face basic questions: How far ahead or behind are we? What does the adversary know that we do not? Are there opportunities to gain advantage through sabotage or misinformation? And how does this bear on the future of international politics?

This is the realm of scientific intelligence. Within this domain, all of the usual challenges of the spy trade — and there are many — are compounded by the fact that the topics of interest are at the very frontiers of human knowledge. As Samuel Goudsmit, a key figure in Vince Houghton’s latest book, The Nuclear Spies, observed, “a Mata Hari with a Ph.D. in physics is rare, even in detective fiction.” Houghton’s book contributes to our understanding of scientific intelligence by explaining how it first emerged in the United States — as atomic intelligence — during World War II and the early Cold War.



The Nuclear Spies centers on two key early cases of atomic intelligence, one a success and the other a failure. During World War II, American intelligence ultimately concluded (correctly) that the Germans were well behind in the race to build an atomic bomb. Yet despite this initial success, only five years later the postwar U.S. intelligence apparatus failed to predict the first Soviet atomic bomb test in August 1949. The United States lost its atomic monopoly with no warning at all from its new intelligence establishment. This is the puzzle that drives Houghton’s book. “Considering how successfully the United States conducted the atomic intelligence effort against the Germans in the Second World War,” he asks, “why was the U.S. government unable to create an effective atomic intelligence apparatus to monitor Soviet scientific and nuclear capabilities?”

The answer, Houghton argues, lies in the organization of intelligence. Because American fear of German technological prowess was so great, he writes, Manhattan Project chief Lt. Gen. Leslie Groves was permitted to build and operate a centralized intelligence system within the atomic bomb program. This centralized approach to atomic intelligence was “the key component in the success of the American effort against the German atomic bomb program.” But as Houghton claims, “the U.S. centralized atomic intelligence system was dismantled after the Second World War.” “The resulting atomic intelligence organization,” he argues, “failed in all three aspects of the intelligence cycle … As a result, both military and civilian policymakers were given the impression that the Soviet atomic program was not of immediate concern.” Centralized scientific intelligence, Houghton posits, is superior scientific intelligence.

The Nuclear Spies is an engaging, well-researched volume that provides a good overview of early U.S. atomic intelligence. The writing is clear and the stories are compelling, making The Nuclear Spies an interesting and accessible overview of a complex and important topic. A significant shortcoming of the book, however, is that the evidence Houghton marshals does not substantiate his argument on how scientific intelligence should be organized. Regardless, the book provides a useful narrative of important episodes in early U.S. nuclear and intelligence history, while also hinting at larger themes that have played an enduring role in U.S. nuclear weapons policy.

To Centralize, or Not to Centralize?

Houghton describes the early history of U.S. atomic intelligence in the six chapters that comprise the core of the book.

Chapters 1–3 center on U.S. efforts to assess the German atomic bomb program. Late-1930s German advances in fission research, as well as the Nazi acquisition of key European research labs and resources through conquest and “the aura of German science,” all contributed to the belief that the Nazi regime was probably hard at work developing this new and powerful weapon. For many American scientists, “the thought of German superiority drove them almost to panic.” Consequently, they successfully lobbied Vannevar Bush, the chairman of the Office of Scientific Research and Development, to direct the establishment of the United States’ first scientific intelligence program in the summer of 1942.

This novel intelligence effort faltered until September 1943, when it was subsumed within the Manhattan Project under the leadership of Groves, and eventually evolved into the famous Alsos Mission. Advancing just behind American invasion forces, Alsos teams of scientists and soldiers captured German physicists and facilities to advance U.S. knowledge of the presumed German atomic program.

Chapter 4 describes the culmination of the Alsos Mission. After concluding that Nazi Germany was not in fact ahead of the United States in nuclear research, the mission’s main focus became preventing German scientific facilities, resources, and know-how from falling into Soviet Premier Joseph Stalin’s hands. This marked the end of Washington’s fears of a German atomic program, but the beginning of its concerns about future Soviet nuclear developments. Tales of derring-do are woven through an excellent description of key personalities making tough choices. The perennial issue was determining how to collect aggressively without inadvertently revealing the United States’ own progress towards the bomb to either the Germans or the Soviets. Readable, well-researched, and nuanced, Houghton’s early chapters provide a fresh — and refreshing — treatment of events that many scholars of nuclear and intelligence issues probably think they already know well.

From here, Houghton’s focus shifts towards the failure of U.S. atomic intelligence in the Soviet case. He describes massive postwar changes in the organization of American scientific intelligence that took place during the early Cold War. The net result was that the formerly centralized atomic intelligence system became diffuse. Ultimately, several factors — widespread belief in the backwardness of Soviet science, the perceived challenge of innovation in authoritarian regimes, and the basic problem of accessing relevant information — all played a role in the intelligence failure. Even so, the key culprit in Houghton’s telling was the shift from a centralized to a decentralized organizational structure for U.S. atomic intelligence.

Here lies the key weakness in the argument presented in the book’s conclusion. While Houghton claims that the organization of U.S. intelligence made the difference between success in the German case and failure in the Soviet case, the evidence he presents suggests otherwise. The United States was able to conclude confidently that Germany was not building the bomb only after it gained access to German scientists and facilities through invasion. In contrast, whatever beliefs senior American officials may have had about the weakness of Soviet science, the fact was that Stalin’s regime was an immensely tough target for U.S. intelligence. Opportunities to interrogate scientists and explore key labs that were available in the German case did not exist in the Soviet case. Thus, whatever other factors may have been involved, the simple ability to access relevant information — not the organization of intelligence — seems to explain much of the variation in outcomes that motivates Houghton’s study.

Origin Stories 

Despite this shortcoming, Houghton makes a number of major contributions to our understanding of early American nuclear history. In particular, The Nuclear Spies touches on two themes that would develop into enduring features of U.S. nuclear weapons policy, though they were still nascent in the pre-1949 period covered by Houghton.

The first is Houghton’s account of the earliest examples of U.S. counterproliferation policy in action. The United States was determined to stymie or delay any efforts by either enemy Hitler or wartime ally Stalin to develop the bomb. Gripping illustrations abound. In December 1942, for instance, American atomic scientists devised “an elaborate and ruthless plan” to kidnap German physicist Werner Heisenberg. Norway’s stock of heavy water and the Norsk Hydro plant that produced it were the target of three separate commando raids, as well as an attack by 140 B-17 bombers, between October 1942 and February 1944. Additional bombing raids on German atomic targets were undertaken in part because “[t]he killing of scientific personnel employed therein would be particularly advantageous.”

Later, as the source of U.S. fears shifted from Germany to the Soviet Union, Houghton recounts the story of Operation Harborage. Led by a reinforced corps comprised of two armored divisions and an airborne division, Alsos Mission members swept in front of advancing French forces to capture German atomic facilities and scientists in southern France. Because leading French physicist Frederic Joliot-Curie held communist sympathies, the goal of the operation was to ensure “that nothing that might be of interest to the Russians should ever be allowed to fall into French hands.”

In subsequent decades, American efforts to slow, halt, and reverse the spread of nuclear weapons would become a durable element of U.S. grand strategy. Although this point and its long-term implications are not developed in the book, Houghton reveals that the roots of this policy run deep. The United States, he shows, embraced the business of counterproliferation even before it had succeeded in building its first atomic weapon.

The second major theme that The Nuclear Spies highlights is the selective linkage between atomic intelligence inputs and U.S. nuclear policy choices. Frequently, the United States has proactively girded itself against threats that have not yet emerged. Occasionally, it has restrained itself despite evidence of growing adversary nuclear capabilities.

For example, according to Houghton, between the late 1930s and March 1945, fear of a German bomb was the driving factor behind America’s own atomic research and development program. Yet even after the Alsos Mission proved that the Nazis were well behind the Americans in atomic development, work on the bomb continued apace. News that Germany was not racing towards the bomb did not alter Washington’s determination to rapidly complete the Manhattan Project and continue growing its supply of fissile material. All that changed was the underlying policy rationale. With Germany nearing defeat, the possibility that the Soviet allies could someday become adversaries quickly became the central concern driving the ongoing development and production of U.S. nuclear weapons.

A similar pattern of threat anticipation was evident in the lead-up to President Harry Truman’s January 1950 decision to pursue the development of the hydrogen bomb. On July 1, 1949, nearly two months prior to Moscow’s first atomic test, the Central Intelligence Agency estimated that the Soviet Union could not build a bomb before mid-1951. That same month, Truman commissioned a National Security Council study on the desirability of a “proposed acceleration of the atomic energy program.” When the report was completed in October, its authors had reached the unanimous conclusion that accelerating atomic development would be militarily useful, technically feasible, and economically beneficial.

Militarily, the Joint Chiefs of Staff believed that “this accelerated program will constitute a net improvement in our military posture both as a deterrent to war, and as preparation for war should it prove unavoidable.” Diplomatically, the committee argued that “in the light of the North Atlantic Pact … it appears likely that Western Europe would consider an expansion of our program not only a desirable development but also positive evidence of our intent to increase our military strength for the security of all.” From a technical and financial perspective, the Atomic Energy Commission concluded that “it is probable that atomic bombs may be employed economically in lieu of conventional bombs against relatively small targets.” Crucially, the report’s authors also concluded that “the recent atomic explosion in the USSR increases the urgency with which this proposed program should be undertaken and executed, but this acceleration should be clearly understood to be a projection of previous plans based on our own capabilities, rather than as a counter-development to the Soviet explosion.” For Truman himself, the fact that the Soviet Union might someday be able to build a hydrogen bomb seemed especially important. Thus, many forces augured towards Truman’s January 1950 decision to develop the hydrogen bomb. But the recent Soviet atomic test and related intelligence failure were not among them.

This sort of fickle relationship between intelligence, extant threats, and American nuclear policy choices would periodically reemerge in subsequent decades. Throughout the mid- and late-1960s, President Lyndon Johnson and especially Defense Secretary Robert McNamara chose to limit the growth of the U.S. nuclear arsenal despite intelligence estimates which predicted Soviet movement towards numerical parity. In the 1990s, following the collapse of its Soviet nuclear rival, the United States began posturing its nuclear forces to counter an entirely new threat: nuclear-armed rogue states. While senior officials feared that rogue dictators would increasingly challenge American interests around the globe, only one such threat — North Korea — has actually emerged over the past thirty years.

The implication is significant and deserves to be explored further. Major choices about nuclear weapons policy are made at the highest levels because of how they impact what the United States can do and because of the signals they send about what the country might do. Adversaries observe U.S. nuclear policy choices and calculate their own responses. Acting in anticipation of threats may inspire foes to balance against the United States, while exercising restraint despite intelligence warning may suggest weakness. Thus, with his detailed account of the relationship between intelligence inputs and U.S. nuclear policy choices at the dawn of the nuclear age, Houghton has surfaced an enduring issue of fundamental importance.


The Nuclear Spies is a valuable book on the early history of U.S. atomic intelligence. Particularly strong in its discussion of World War II, the Manhattan Project, and the Alsos Mission, it lends texture and nuance to episodes that many readers of this review will know in passing. Its primary weakness lies in its conclusion about the value of centralized intelligence. The book makes its most significant contribution by unearthing the roots of what would become important threads in the subsequent history of U.S. nuclear policy. The persistence of American efforts to inhibit proliferation, including through force, as well as the uneven relationship between intelligence inputs and policy outcomes are both important. By describing the origins of these two recurring themes, Vince Houghton has made a valuable contribution to our understanding of the history of U.S. nuclear weapons policy.



Timothy P. McDonnell is a research analyst at CNA where much of his work centers on nuclear policy issues. Previously, he has been a Stanton nuclear security fellow at the Carnegie Endowment for International Peace as well as a pre-doctoral fellow at the George Washington University’s Institute for Security and Conflict Studies. He earned his Ph.D. in political science from Massachusetts Institute of Technology, where he was a member of the Security Studies Program. The views expressed here are his own.

Image: U.S. Army