How Dangerous? History and Nuclear Alarmism

Despite almost 70 years of nuclear nonuse, years in which the threat of a global thermonuclear conflagration has decreased enormously, the rhetoric of fear surrounding nuclear proliferation and nuclear use continues. The United States has taken the lead in fostering those worries and has pursued bold—and at times aggressive—policies, from global arms control to permanent alliances to threats of coercion and even preventive war, to meet such declared danger. That increasing response, however, seems out of proportion with what would seem to be the decreasing threats. How do we explain the puzzle?

Often, scholars have offered suggestions, focusing on what might be thought of as subrational explanations—such as bureaucratic or organizational politics, ideology, or the sway of parochial domestic considerations—to describe something that is otherwise a mystery: why so much attention, treasure, and blood to a situation that, at least on the surface, seems to warrant it far less than in the past, where the very medicine at times appears worse than the cure? One might argue that those very costly policies are what prevented nuclear tragedy,and such arguments could be right: it is hard to prove or disprove such a counterfactual. Still, the gap between the threat and the remedy seems large, especially given how aggressive U.S. counterproliferation policies have been in recent years.

To answer why the world—the United States in particular—has been alarmist, we need to understand how nuclear weapons influence international politics, both now and in the past. For example, why has there never been a thermonuclear war? That question is obviously extraordinarily difficult, if not impossible, to answer. We have enough difficulty making sense of things that have actually occurred. After all, despite the labors of countless scholars from around the world, assessing millions of pages of documents, no one agrees on what caused the First World War. The same can be said about the origins, course, and consequences of any number of other geopolitical events. Notwithstanding the confident claims of countless theorists, we don’t really know why we have never had a thermonuclear war. We are understandably eager to have an explanation for the most important nonevent in human history, if only to see if there are lessons that can be applied today to keep the streak going as long as possible. It is a daunting task, far more challenging than we acknowledge, and many of the research questions that we do focus on are merely proxies for that larger concern. In the end, many of our debates surrounding nuclear weapons—such as why states do or do not build the bomb, how they behave when they get it, or how and when deterrence works—are animated by our beliefs and desire to better understand why there has never been, and we hope will never be, a thermonuclear war.

This chapter moves beyond many of the deductive and theoretical assessments of those questions to find a better historical foundation for our analysis.¹ Instead of telling how history suggests the United States should think about Iran or North Korea’s nuclear program, nuclear terrorism, or the fear of nuclear tipping points and proliferation cascades, this chapter suggests three larger points. Wrestling with the history of the nuclear question can, we hope, contribute in a meaningful way to how we understand the consequences of the thermonuclear revolution and can perhaps even lead to more effective policies.

The first point pertains to method: all historical work involves an intense dialogue between the empirical and the conceptual. The evidence that historians find informs our theories of the world and vice versa, back and forth in an interactive fashion.² All good historians know that point, but many outside the guild, including important policymakers and international relations experts, have a different viewof how we operate. Historians are often thought of as either storytellers or collectors of “data.” Policymakers see Michael Beschloss or Doris Kearns Goodwin on television, read Robert Caro’s magisterial biographies of Lyndon Johnson—or on the nuclear question, Richard Rhodes—and think of the historian as a sort of bard who weaves tales. There is also the image of the less famous, academic historian, who is working away in a dusty archive and collecting reams upon reams of documents that might be fed into the models and regressions of social scientists. Although outsiders cannot help but be impressed by the beautiful prose and the carefully crafted narratives, or by the stacks upon stacks of documents, there is little sense that important, serious arguments are being made or that there is an explicit conceptual framework or theory for understanding the world.³

Why does correcting those caricatures—even while acknowledging that there is some truth to them—matter? The answer touches on the second point: any historian working in the nuclear policy area immediately confronts an enormous, and in many ways intimidating, conceptual hegemon: the strategic studies literature on nuclear weapons and its influence on world politics. A powerful corpus of ideas, based largely on deductive reasoning, began to emerge almost as soon as the first atomic bomb was dropped. At that time, Bernard Brodie declared: “Thus far the chief purpose of our military establishment has been to win wars. From now on its chief purpose must be to avert them.”⁴

For almost 70 years, strategists trained in the natural sciences, mathematics, economics, and—most prominently—political science have been working to develop theories surrounding nuclear dynamics and statecraft. Several generations of that work have shaped the conventional wisdom, established the issues open for debate, and provided us with the framework with which to investigate those questions.⁵ Although there is some reason to question whether the strategists were as influential with policymakers as is often claimed,⁶ that body of work is extraordinary from an intellectual history perspective, both in its sophistication and its influence on public discussion. It is a literature, however, almost bereft of a historical sensibility and of the skepticism, comfort with uncertainty, and humility the study of the past brings with it. I have had more than one prominent scholar in the field tell me that we know all we need to know about how nuclear deterrence works and, by extension, about why we have never had a thermonuclear war. The power and certainty of that theoretical literature act as their own deterrent to rigorous and creative thinking about why and how states have made decisions about nuclear weapons over the decades.That point leads to a third issue: the question of policy relevance. Policymakers would benefit from a greater understanding of this nuclear history, just as scholars should be willing to engage the concerns and interests of decisionmakers. Unfortunately, as a discipline, aca demic history has long been wary of power, believing it corrupts those scholars who try to court it and allows those in power to misuse the past for less than noble purposes. The standard position of even the most policy‐​empathetic historian when asked for his or her view on what the past tells us about a contemporary issue is “it’s complicated,” which, in the end, is not a very helpful answer. When people talk about “policy‐​relevant work,” they typically mean scholarship that provides accurate forecasts about the future and, if not theories, at least generalizable rules of thumb that are parsimonious. All of those demands cut deeply against the instinct and practice of the historian, who emphasizes historical context, unintended consequences, and the complex interaction of multiple forces. That poor fit, one would think, would provide powerful incentives for the historian to stay as far away from policy as possible.

Avoiding policy relevance in nuclear history, however, isn’t the right answer. Elsewhere, I’ve laid out what I think historians can contribute to policymaking: there is a whole set of insights and, perhaps more important, a sensibility that comes from studying the past, both of which are bound to improve decisionmaking.⁷ The potential contributions that can be made by historical work stack up quite nicely when compared with the efforts of other disciplines, such as economics and political science. Any effort to come to terms with why we have not had a thermonuclear war is bound to be of great and understandable interest to people in positions of great responsibility, whether a historian wants his or her work used in that way or not. Scholars mining archives around the world to understand how nuclear states made decisions about nuclear weapons and how the thermonuclear revolution affects statecraft, as well as national and international security, are bound to intrigue, if not help, decisionmakers. Such knowledge can usefully supplement, if not at times replace, the dominating, deductive views of the strategy world.

One of the virtues of historical work that is often missed in the deductive and theoretical literature on nuclear weapons is something I’ve called “horizontal history,” the connections between issues over space, as opposed to time. Social science scholars often focus like a laser on one particular issue, say, nuclear strategy or America’s relations withChina, and see how it develops over time. But at the top levels of policy, all sorts of seemingly separate issues turn out to be interconnected in surprising ways. The story of how I stumbled into nuclear history, quite by accident, reveals both the persistence of horizontal history and the benefits of following the documents wherever they might lead. It all began with research on postwar international monetary relations.⁸

Beginning in the late 1950s, four successive presidential administrations (Eisenhower, Kennedy, Johnson, and Nixon) strived to find ways to end the balance‐​of‐​payments deficit and ameliorate its effects. None of the macroeconomic tools (e.g., raising interest rates, restricting the domestic monetary supply, enacting new trade restrictions or capital controls, or devaluing the currency) were attractive to U.S. officials. Those measures would slow or even deflate the domestic economy, which was certain to be unpopular.

Policymakers looked instead for ways to dramatically reduce the amount of monies spent abroad. By far, the largest account they could control was the cost of stationing U.S. troops and their families overseas. Most of those troops were part of America’s commitment under the terms of the North Atlantic Treaty Organization (NATO) agreement, specifically defending Western Europe from the Soviet Union. Not coincidentally, the countries with the largest balance‐​of‐​payments surpluses were the most obvious beneficiaries of America’s expensive military protection: West Germany and France. Reducing the U.S. conventional force posture abroad was, from a domestic political and economic perspective, an ideal solution. Presidents Eisenhower, Kennedy, and Johnson and many of their closest advisers not only were willing, but also at times appeared eager, to pull American troops from Western Europe.

That account was at odds with the standard accounts, which claimed the Kennedy administration had increased American conventional forces and developed more nimble nuclear packages as the basis for the strategy of “flexible response.” Contemporary observers certainly had reason to believe that story was true, as Robert McNamara laid out the strategy, thereby incorporating many of the views of the strategy community, in a secret speech to NATO and in a public version in Ann Arbor, Michigan, in the spring of 1962. Yet the documents leading up to and after both speeches painted a different picture from the public rhetoric. No one really seemed to buy the core logic of the strategy, and McNamara himself was one of the leading advocates throughout the 1960s for steep U.S. troop withdrawals.

There was a striking contradiction: the United States embracing a strategy that required more conventional forces while actively seekingto bring American troops back from Europe. And that wasn’t the only such case. U.S. policy on tactical nuclear weapons, for example, pulled in all sorts of different directions and was never really resolved at the highest political levels. The Single Integrated Operational Plan (SIOP) did not really become all that more flexible, and, as far as one could tell, U.S. nuclear strategy was still largely based on the massive, preemptive strike articulated by Secretary of State John Foster Dulles a decade earlier.

The man responsible for implementing strategy in Europe, NATO’s supreme allied commander in Europe, General Lyman Lemnitzer, actually “forbid the use of the term” flexible response “throughout SHAPE [Supreme Headquarters Allied Powers Europe] and Allied Command Europe.” Lemnitzer complained that “so many of [his] people didn’t really know what flexible response meant.”⁹ And the official history of America’s nuclear command‐​and‐​control effort contends that “to the extent it amounted to a doctrine, it was open to different interpretations, and it is not easy (if at all possible) to find a single coherent, clear statement of it, even among authoritative pronouncements of the President and the Secretary of Defense.”¹⁰ When Nixon’s secretary of defense, James Schlesinger, examined the war plans, he and his team were stunned to see the rigid, massive SIOP everyone thought had been discarded by the Kennedy administration.

The documents did not comport with the received wisdom in the largely deductive strategy literature.¹¹ The literature was clean, crisp, and driven by a powerful logic. But the policies themselves were messy and pulled in different directions.¹² That history teaches us to be skeptical of bureaucratic political explanations for something as important as nuclear policy.¹³ When one reconstructs U.S. national security policy on the basis of the documentary record, one gets a sense that on the questions that truly matter—and issues of war and peace, especially nuclear war, certainly qualifies—what the president decides actually matters and is almost always carried out.

And in that case, an underlying strategic logic was driving those policies. The flexible response doctrine was as much about nuclear nonproliferation vis‐​à‐​vis America’s allies—West Germany, especially— as a nuclear deterrent strategy versus our adversary. After Great Britain and France developed their own nuclear capability, it was only natural that West Germany would also be interested in those weapons. The prospect was deeply unsettling, not just to the Soviets but to the rest of Europe as well.¹⁴ By strengthening extended deterrence, the flexible response strategy was aimed at reassuring the West Germans and lessening theirdesire for their own nuclear forces. It also allowed a nonproliferation policy that, under the cover of an alliance strategy, did not overtly discriminate against the key target, the Federal Republic of Germany (i.e., West Germany). That—as much as anything the Soviets were doing—was the driving logic of the strategy. A search in the archives to explain U.S. international monetary policy came, most unexpectedly, to reveal the enormous gap between the rhetoric and reality of U.S. military strategy in Europe. It also encouraged a reexamination of many of the core precepts of the strategic studies literature.

Three big questions stood out: (a) Did the United States care far more about stemming the spread of nuclear weapons than the strategic literature had recognized? (b) Relatedly, was its focus simply on particular complexities surrounding nuclear weapons and West Germany, or was there a broader concern with nuclear proliferation writ large? and (c) Could U.S. nuclear strategy be seen as both a tool of nuclear nonproliferation and an effort to deter the Soviet Union? What did the documents reveal?

The archival record—specifically Roswell Gilpatric’s papers at the John F. Kennedy Presidential Library—revealed unexpected, surprising insights relevant to contemporary debates over nuclear proliferation. As McNamara’s deputy, Gilpatric was involved in both the deliberations over balance‐​of‐​payments‐​inspired troop withdrawals and the status and strength of U.S. nuclear forces. After Gilpatric left office, President Lyndon B. Johnson asked him to chair a committee charged with determining how the United States should respond to China’s detonation of an atomic device in October 1964. China’s nuclear status was deeply disconcerting, and top policymakers wondered both how to react to China specifically and what effect the test would have on nuclear proliferation more generally. There was no agreement within the administration over what to do—some advocated preventive attacks; others suggested negotiating with China—so the president created an external blue‐​ribbon group to provide answers.¹⁵

The so‐​called Gilpatric Committee looked beyond the question of how to respond to China’s acquisition of nuclear weapons to the whole issue of how the United States should think about and deal with nuclear proliferation. Up to that point, the general attitude of most U.S. policymakers was that although the spread of atomic weapons was regrettable, the United States could do little to stop it. The American experience with France had been influential—all the United States had received in return for its efforts to halt its nuclear program had been mistrust andenmity. Some, including Secretary of State Dean Rusk, suggested that since proliferation was inevitable, the United States should get ahead of the curve and provide nuclear weapons to friendly aspirants like India and Japan. In the end, few people thought much could be done.

The Gilpatric Committee helped transform that attitude. First, the committee explored the consequences of a proliferated world and the costs of preventing it. The committee analyzed options ranging from aggressive rollback of nuclear states (including preventive action against allies) to a fully proliferated world (aided by the United States). It investigated difficult political issues: Should China be attacked or appeased? What would happen to American power in a proliferated world? How could West Germany be kept nonnuclear? Should the French and even the British be coerced out of the nuclear business? Was it necessary to escalate military activities in Southeast Asia to demonstrate to allies like Japan and Australia that the United States would stand up to nuclear‐​armed bullies like China?

The archives reveal a story of a fairly dramatic, and by no means inevitable, shift in global U.S. nuclear nonproliferation policy. The Gilpatric Committee had recommended that the United States make nuclear nonproliferation a far higher priority and use every policy short of preventive action to achieve the goal. President Johnson personally intervened to make that policy shift happen, and it laid the groundwork for the 1968 Nuclear Non‐​Proliferation Treaty, which remains the bulwark of nonproliferation efforts to this day.¹⁶

Those insights were at odds with the strategy literature. The politics of the German question, the worries over the spread of nuclear weapons, and the policies needed to assure allies were as important as, and at times more important than, the strategic nuclear rivalry with the Soviets during the 1960s and 1970s. That disparity not only puts the nuclear question in a different light, but also provides a different view of the Cold War and its relationship to the nuclear question.

According to the strategy literature, the history of the Cold War was often synonymous with the history of the strategic nuclear rivalry between the superpowers: any change in strategy, whether it was the New Look or flexible response or mutually assured destruction or détente, reflected a change in Cold War realities. But there were other, powerful forces at work that were driving nuclear dynamics. For example, most of the nuclear aspirants of the postwar period—be they France or Great Britain, India or Pakistan, China or Japan, Israel or Egypt, South Africa or Brazil—were motivated less by Cold War dynamics than by their own regional security or desire for prestige.Furthermore, the United States and the Soviet Union had powerful incentives to work together to limit the spread of nuclear weapons, regardless of their other conflicts. The main picture of nuclear nonproliferation from the mid‐​1960s onward is that of Russians and Americans working together to keep allies and ideological fellow travelers such as West Germany, Japan, China, and Yugoslavia down.

Those findings raised new questions with respect to current nuclear policy. Was the dramatic shift in nuclear nonproliferation policy during the 1960s the correct choice? And what were the lessons for contemporary policy? On the one hand, theorists such as Kenneth Waltz, Robert Jervis, and others argued that nuclear proliferation was not to be feared. While few strategists went as far as Waltz to actually welcome or encourage the spread of nuclear weapons, the consensus was that proliferation was not the end of the world. Those theorists explained that nuclear weapons had powerful deterrent effects. Very few political goals were worth a nuclear war, and although states might push their claims to a certain point, they would back off far short of nuclear war. By that logic, nuclear deterrence was a stabilizing force in international politics.¹⁷

The debates over new nuclear threats took on added urgency in the public mind in the 2000s. The 9/11 attacks on the United States and the focus on access to weapons of mass destruction by so‐​called rogue regimes—highlighted in the 2002 U.S. National Security Strategy— seemed to push American policy toward an even more aggressive, almost preventive, nonproliferation strategy. The threat of a rogue nuclear state or the acquisition of a weapon by a nonstate actor was seen as not simply dangerous but likely. The war against Iraq, as well as threats against Iran, appeared to be driven in large measure by a fear that the post–Cold War world faced new and more dangerous types of threats than any the Russians and Americans had faced.

Those views seemed, at best, alarmist. The unlikely use of one or two crude fission bombs, no matter how horrific, could never compare with the threat of a full‐​scale thermonuclear exchange between the superpowers, a nightmare that seemed at times in the late 1950s and early 1960s to be terrifyingly plausible. Furthermore, Mao’s China was far more “rogue” than Iraq, Iran, or North Korea. The People’s Republic of China had fought U.S. forces in Korea, supplied the Viet Cong, threatened Taiwan and its other neighbors, and attacked democratic India. It had undergone domestic upheaval that had led to millions ofdeaths, and Mao himself had used highly irresponsible rhetoric about prevailing in a nuclear war. If ever a state was resistant to deterrence, it was not Saddam Hussein’s Iraq or the Iran of the mullahs, but Mao’s China. Yet the United States had not overreacted, had not launched preventive attacks, but instead had learned to live with a nuclear China while dramatically strengthening its global efforts to limit proliferation. Its reward was not the so‐​called tipping point of nuclear weapons in Japan, Australia, Indonesia, and elsewhere but was an adversary that built few nuclear weapons, remained deterred, and, in short order, became a de facto ally.

Did that mean the George W. Bush administration’s policy was both folly and a radical break from the past? It certainly seemed that way at first blush, though the Bush policy shared important historical antecedents.¹⁸ Nuclear weapons were terrifying, to be sure, and they should be at the top of the policy agenda for any U.S. president. But policymakers appeared to overstate the threat posed by so‐​called rogue and nonstate actors, at least compared with far better‐​armed nuclear challengers (i.e., the Soviet Union) from decades earlier. Worse, by overstating or misrepresenting both the past and the present, there was a danger of the medicine being worse than the cure.

Looking deeper, it became clear that that preventive instinct, the desire to “inhibit” nuclear proliferation, was not, in fact, new. American policymakers had seriously considered preventive action under three administrations led by Democrats: specifically, the Soviets in the 1940s, the Chinese in the 1960s, and the North Koreans in the 1990s.¹⁹ What was going on here? Mira Rapp‐​Hooper and I undertook research that convincingly demonstrated that deep similarities existed between those “preventive inclinations” over time, administrations, and even structural shifts in the international system. And as we examined the issue in greater detail, it became clear to us that the United States had been willing to brandish coercive measures short of military action to prevent proliferation, even against its own allies.²⁰ From France in the 1950s to Pakistan, South Korea, and Taiwan in the 1970s, the United States went to great lengths—short of the use of force—to limit the spread of nuclear weapons.

Defensive realists and strategists did not have very compelling answers to explain that persistent American inclination to limit proliferation, in the same way they did not understand why the United States continued—and in some cases expanded—its security assurances and nuclear umbrella after the Cold War had ended and the Soviet Union had collapsed. Did the United States simply not understandthe compelling and stabilizing logic of nuclear deterrence? Did U.S. policymakers not see that nuclear weapons prevented wars and lesser military interventions and favored the status quo?

Or could it be that since the dawn of the nuclear age, American policymakers fully understood the power of nuclear deterrence and recognized, first, as a superpower and then as a global hegemon, that deterrence could be oriented against the United States? Despite being the world’s strongest state, with overwhelming superiority in every conceivable form of power, from economic to soft to conventional, the United States did not especially prize stability or the status quo. What it understandably wanted was the freedom to act in the world as it saw fit, even if it meant using military force or intervening in the internal affairs of other countries. But nuclear weapons, even in the hands of otherwise impotent states, deterred the United States from doing things it wanted. The United States, therefore, had a deep strategic reason to limit nuclear proliferation: not for moral reasons, nor even because of the fear of nuclear war, but because nuclear deterrence limits U.S. freedom to act.

It turned out that the strategy literature had fundamentally missed what Rapp‐​Hooper and I came to call America’s “strategies of inhibition,” or its efforts to limit—if not completely eliminate—nuclear weapons from the planet. Sometimes, those efforts were coercive, like threatening preventive military action or sanctions; sometimes, they were more normative or legal (arms control treaties); and still other times, they involved cooperative tools like alliances or joint nuclear doctrines. Sometimes, those inhibition strategies (e.g., flexible response) went hand in hand with other goals, such as deterring the Soviet Union. At other times, such as cooperating with the Soviet Union to negotiate the Nuclear Non‐​Proliferation Treaty, the inhibition strategy seemed at odds with the grand strategy of containing the Soviets. It was clear, however, that something important had been missed.

The new conceptual understanding helped explain things that had made little sense before. Why did the United States continue preemptive counterforce strategies, even after the Soviet Union achieved secure second‐​strike forces? Why did the United States pursue missile defense; eschew no first use; and spend hundreds of billions of dollars on command, control, communication, and intelligence of nuclear forces— postures that puzzled most strategists after the superpowers achieved parity? Why did the United States obsess about the nuclear forces of otherwise sixth‐​rate states like North Korea, Iraq, and Iran? Why did the United States not only not abandon its security commitments andalliances after the Cold War but also actually expand and strengthen them? The new conceptual lens suggested that those strategic tools were adopted in large measure to dampen proliferation, either through coercion or assurance. The requirements for such a strategy are much different from—and much more difficult than—a strategy of simply deterring nuclear use by an adversary. The United States was not afraid of others; it was worried about the limitations that nuclear weapons placed on its own ambitions.

Historical analysis revealed that both the alarmist views and the critique by defensive realists missed the mark. Although the fears of nuclear proliferation were overstated, the cause was less bureaucratic politics or ideology than good old‐​fashioned U.S. interests. Nor had policymakers lost faith in the power of nuclear deterrence; rather, they were loath to see it used by others in ways that would limit their freedom of action.

There are two other cases in which deep historical work might challenge the conventional wisdom. First, nearly every graduate student from the strategy community is taught that a fundamental cornerstone of nuclear dynamics is the clear and important distinction, first laid out by Thomas Schelling, between deterrence and compellence.²¹ Deterrence, according to the common view, is supposed to be easier and compellence harder; furthermore, deterrence is the policy of the status quo power and compellence that of the supposed aggressor. Most of the stylized history of the nuclear age is arranged neatly into those categories: crises are sorted into an aggressor trying to compel and a status quo state trying to deter. The Soviet Union, for example, is coded as the aggressor using compellence during the Berlin crisis and Cuban missile crisis, whereas the United States is the status quo deterrer.

That framework for understanding how nuclear statecraft actually works is helpful in several ways. Looking at the documents on the U.S.-Soviet crises over Berlin in the late 1950s and early 1960s, however, one wonders how meaningful those distinctions were.²² For example, if deterrence was easier, it should have been relatively straightforward to prevent the Soviets from taking over West Berlin, but much harder to compel them to leave East Berlin, or all of East Germany. But presumably, the Russians would understand that before moving in, so how could they be deterred from taking the city in the first place? More fundamentally, analyzing the 1958–1962 period makes clear that the status quo—and who is the “compeller” and who is the “deterrer”—is often in the eye of the beholder. The Soviets were trying to change the status of a citythat even the Americans recognized was completely untenable in the long run. And the Soviets were doing it largely to deter the Americans from policies that were leading to the nuclearization of the Bundeswehr, which would have been deeply unsettling to the status quo.²³

Or consider other examples. Did Stalin order the blockade of Berlin in 1948 to deter the creation of the Federal Republic of Germany (FRG), or was he trying to compel the West to abandon a policy of incorporating the FRG into the Western Alliance? Or if we look at a prenuclear case: in 1914, was Austria trying to compel Serbia to abandon its policy of creating a greater Serbian state at Austrian expense (and to compel Russia to abandon its policy of supporting Serbia in that area), or was Austria trying to deter Serbia from challenging the status quo? In the end, how useful was that core idea of the strategy literature, once one got into the documents and reconstructed how policy was actually made?

Consider another fundamental conceptual cornerstone of the strategy world: the need to have nuclear arms control to calm the so‐​called security dilemma that drives nuclear arms races and that can lead to unintended nuclear war. One of the unimpeachable truths of the strategy and arms control community is that the Strategic Arms Limitation Talks (SALT and SALT II) between the Soviet Union and the United States were unalloyed goods, the cornerstone of strategic stability. But the documents might reveal a different picture. The vehemently negative reaction to the negotiations within certain domestic circles in the United States, which gave rise to neoconservatism, is well‐​known.²⁴ There is evidence that the Soviet military was furious as well, which may have led to the deployment of SS-20 missiles.²⁵ The SALT agreements inspired great mistrust and unhappiness among many of America’s European allies—worried as they were about the credibility of America’s extended deterrence commitments—and the deployment of the SS‐​20s generated a crisis in NATO.²⁶ Those efforts to establish strategic stability, it could be argued, perversely helped undermine détente by the late 1970s.²⁷

It would be useful for a historian to explore the relevant archives in the United States, Europe, and Russia to explore what really drove arms control and to assess whether it was as valorous as many strategists claim. Policy is all about choices and tradeoffs—historical research might suggest that the enormous political capital expended on the SALT negotiations between the Russians and Americans could have been more productively spent on other issues. Going back and forth between the evidence and testing and erecting new conceptual frameworks might provide real insight into how the nuclear policy process works.

Almost 70 years ago, an American B-29, the Enola Gay, dropped a gun‐​fission weapon made with uranium 235 on the city of Hiroshima, Japan. Three days later, a plutonium device was dropped on the city of Nagasaki. That those two detonations transformed the world of politics and international affairs forever is universally accepted. The precise meaning and consequence of that legacy, however, are deeply contested. Why were nuclear weapons never used again? And why, despite that fact, is U.S. policy so obsessively concerned with nuclear use, even as the risks of a catastrophe have fallen? And how are those two questions linked?

The chapter offers suggestions but no clear answers. On the one hand, most people are understandably repulsed by the existence of weapons whose use in large numbers could end human civilization. Some experts contend that we’ve avoided a catastrophe by sheer luck that is unlikely to continue, and restraining, reducing, and eventually eliminating those weapons from the planet are the international community’s most important priority. One can look to the past to make that argument. On the other hand, as we have seen, others argue that nuclear weapons have served as a sort of necessary evil, preventing the kinds of murderous, global conflagrations that plagued the first half of the 20th century. Advocates of nuclear deterrence contend that millions of people and their descendants may be alive today because of the caution those horrific weapons induce in even the most aggressive and tyrannical governments. There is certainly evidence for that view in the archives.

Those larger views, of course, frame many of the contentious discussions surrounding contemporary challenges; consider the furious debate over what to do about Iran’s nuclear program. Iran’s aggressive behavior in the Middle East, its disturbing rhetoric about Israel, and its relationship with terrorist organizations convince many that the United States must do all it can, including using or supporting force, to keep Iran nonnuclear. Others are equally convinced that a nuclear Iran can be easily contained and deterred, and that using force would be a disaster. Kenneth Waltz went so far as to argue in the lead essay in Foreign Affairs that a nuclear Iran would actually stabilize the Middle East and generate peace.²⁸

Who is right? Do nuclear weapons make the world safer or more dangerous? Can a deeper understanding of the past, a greater reliance on historical work as opposed to the strategy literature, provide us with more usable insight that can be translated into better policies?This historian would certainly like to think so. The uncomfortable truth, however, is that despite bold assertions from scholars, advocates, and policymakers, we simply don’t know the answers, and additional research into the history of nuclear weapons and strategy is as likely to cloud as to sharpen our views.

The historian can, however, provide needed skepticism and humility about broader claims, particularly those of alarmists. The voluminous and often shrill debate over contemporary nuclear dynamics consistently ignores our abysmal record of explaining and predicting nuclear politics since the start of the atomic age. Once the Soviet Union replaced the defeated Imperial Japan and Nazi Germany as America’s main foe, as early as 1947, a third world war involving nuclear weapons was considered all but inevitable. Fears of a thermonuclear war between the superpowers abated (somewhat), and concerns turned, even before the end of the Cold War, to cascades of proliferation to dozens of smaller, supposedly less responsible, states that were unlikely to imitate the superpowers’ restraint. In time, nonstate actors, including terrorist groups, would get their hands on those weapons, and some of our leading experts saw a detonation on American soil as a near certainty.²⁹

None of those terrible scenarios, thankfully, came to pass. Does that mean that the advocates of nuclear deterrence are correct? Not necessarily. The declassified documents show that Cold War nuclear crises were often far more unstable and dangerous than we had thought, and the temptations to use nuclear blackmail have been hard to resist. The Berlin and Cuban missile crises would have been unlikely in a world without nuclear weapons.³⁰ The superpowers experienced terrifying nuclear accidents and false alarms. Saddam Hussein’s captured documents and recordings reveal that he wanted the bomb to both deter and coerce. Finally, U.S. nuclear and nonproliferation policies have often been destabilizing and driven as much by interest as fear.

In the end, we are left where we began: it is difficult to explain precisely why something did not happen. Correlation, or the absence of conflict, does not equal causation. Nuclear‐​armed adversaries did not go to war, but it isn’t obvious that the nuclear weapons, per se, deterred them. After decades of global bloodletting, a clash of arms between a war‐​devastated Soviet Union and a United States uninterested in territorial gain was by no means inevitable in a nonnuclear world. In theory, nuclear weapons are best for preventing other states from invading you, but, in more recent times, the prospect of great power conquest has largely disappeared for reasons that appear to have little to do with nuclear deterrence.³¹ Massive increases in agricultural productivity, economic interdependence, technology, norms against violence, and—as we have learned in Iraq and Afghanistan—the high costs of occupation and the power of nationalism mean that conquest rarely pays. Visit Singapore, Dubai, or the Netherlands, and you soon realize that land is no longer power.

Where should that leave us in thinking about our nuclear future? And what role can scholars play in shaping our understanding of the threats we face? More than anything, we should be humble in the face of those terrible weapons, and we should recognize that, despite what you might read in blogs or hear on the campaign trail, we don’t fully understand how nuclear weapons influence statecraft. Almost seven decades later, we still don’t even know whether the atomic bombing of Japan was the cause of its surrender.

My best advice, based on more than a decade of archival research on the question, is relatively modest and unsophisticated. Having fewer nuclear weapons in the world is probably a good thing, but using force or coercion to achieve that goal is probably not. Alarmist rhetoric is not helpful, and the conventional wisdom has likely exaggerated post‐​Cold War nuclear threats, such as tipping points, nuclear use by rogue states, and nuclear terrorism. Although that is not much, perhaps the most useful advice we can give to policymakers facing the awesome responsibility of nuclear stewardship comes from a famous military historian, John Keegan, in his classic Mask of Command: “Indeed, what is asked first of a leader in the nuclear world is that he should not act, in any traditionally heroic sense, at all.”³²