war on the rocks

Continuity From Ambiguity: The Real Role of Nuclear Posture Reviews in U.S. Nuclear Strategy

February 19, 2018

Editor’s Note: This is an excerpt from a policy roundtable on the Trump administration’s Nuclear Posture Review from our sister publication, the Texas National Security Review. Be sure to check out the full roundtable.

In a matter of days, the Trump administration’s Nuclear Posture Review has joined the ranks of Colin Kaepernick and global warming as a shibboleth for one’s political tribe. Critics argue that the 100-page document is dangerously regressive, calls for unnecessary nuclear capabilities, and makes nuclear war more likely. Others praise the Nuclear Posture Review’s emphasis on deterring a rising China and recalcitrant Russia. A few observe that the document largely reaffirms longstanding precepts, intentions, and motivations underlying the U.S. nuclear posture, particularly because it endorses the last administration’s ambitious program for nuclear force modernization. These voices of moderation, however, are in the minority.

Polemics aside, it is misleading to read the Nuclear Posture Review as a straightforward statement of U.S. nuclear doctrine. It is more helpful to think of the review like a political party platform: a formal statement of values and goals crafted by strongly principled individuals who do not always agree but nonetheless must arrive at a rough consensus. This Nuclear Posture Review, like those before it, is not a comprehensive set of prescriptions binding nuclear planners and operators and the vast enterprise that supports them. It is not an internally consistent account of the priorities and values of high-ranking individuals, including the president of the United States or, necessarily, the secretary of defense. Like a platform, the review contains some well-intentioned aspirations as well as many inherent contradictions. Most importantly, as with most party platforms, the document’s primary purpose is to communicate the views of political leaders rather than establish operational requirements.

The ways in which nuclear plans and posture decisions are made in the United States make it inherently difficult to put the Nuclear Posture Review’s most ambitious goals into practice. Declaratory policy — what is said publicly about U.S. nuclear weapons and strategy—is the province of political leaders who face strong political and personal incentives to align rhetoric about nuclear weapons with their preferred approach to foreign policy. Meanwhile, the actual procedures for the employment of nuclear weapons are the responsibility of military planners within U.S. Strategic Command. Unlike political leaders, who focus on nuclear issues intermittently, military planners are challenged to translate abstract political goals into operationally effective real-world plans. The Nuclear Posture Review sits astride these communities, with their divergent priorities and capacities for attention. As a result, presidents and their advisers may find themselves disappointed that these documents do not directly translate into changes in the operational posture.

The history of these reviews suggests that differences in emphasis and content are not a product of deep differences in core values or priorities that have long guided assumptions about the relative utility of nuclear weapons in American security. Nuclear posture reviews have always inhabited the mainstream of the nuclear enterprise — the community of expertise and practice that endures beyond the tenures of presidents and parties. Where these documents do differ is in how their drafters respond to two fundamental questions about U.S. nuclear policy:

  • To what extent does deterrence depend on demonstrating how the United States would use nuclear weapons to prevail against any adversary at all levels of conflict?
  • To what extent does what the United States says about the value and utility of its nuclear weapons affect the behavior of others?

All nuclear posture reviews represent an incoming presidential administration’s answers to these questions and the relative priority accorded to different approaches. In the course of defending their preferred approach to nuclear strategy, however, both supports and detractors of this and past reviews tend to overlook a number of shared assumptions and common conceptual blind spots.  Proponents on all sides are especially likely to overstate America’s ability to influence the behavior of allies, adversaries, and future proliferators through its operational or declaratory policies.

The disjuncture between what nuclear posture reviews set out to accomplish and what they actually achieve should lead observers to consider the documents in the context of broader decisions about the posture and nuclear force planning. Outside observers tend to scrutinize these reviews while failing to familiarize themselves with the content of operational plans and policies. The content of these plans, the assumptions behind them, and the weapons capabilities they support constitute America’s actual nuclear posture.

Same Goals, Different Strategies

Nuclear planning is made difficult because of the lack of strong evidence about how the character and composition of American nuclear forces affect the behavior of others. In the absence of such clarity, decision-makers and experts tend to fall back on their broader worldviews and beliefs about the nature of international politics. Debates about the nuclear posture tend to feature two roughly coherent camps. On one side are those who advocate for a greater role for nuclear capabilities in achieving deterrence and nonproliferation. On the other are skeptics who doubt whether nuclear weapons can deter aggression short of a major nuclear attack. Those in the first camp tend to argue that nuclear weapons backstop American efforts to assure allies, deter adversaries, and prevent proliferation. The second school of thought holds that nuclear weapons can be a liability in these endeavors.

The drafters of the latest Nuclear Posture Review believe that aggression and proliferation can be deterred by making the threat of American nuclear use more realistic, and therefore advocate an expansive role for nuclear weapons in promoting deterrence and nonproliferation. In practice, this means fielding nuclear capabilities that are sufficiently discriminate and low-yield that an American president might conceive of actually using them in extreme circumstances. The imperative of creating a sufficiently believable risk of American nuclear escalation also drives many advocates to favor extensive counterforce capabilities—precise nuclear weapons capable of attacking an adversary’s nuclear weapons and the supporting command and control networks. For advocates, limited options, such as the low-yield submarine-launched ballistic missile called for in the 2018 Nuclear Posture Review, and counterforce capabilities help support U.S. commitments to extend nuclear deterrence to allies. Limited options and damage limitation are the price to pay for extending deterrence to allies.

Importantly, such advocates come from both parties. Democratic and Republican presidents alike have pursued and endorsed low-yield, “flexible” options and damage limitation capabilities. The question of how to make the threat of nuclear use credible not just in cases involving the survival of the U.S. homeland, but also in the defense of allies is arguably the fundamental question in nuclear strategy, animating most of the debate through the Cold War.

Advocates of a more expansive role for nuclear weapons also emphasize the role of these weapons in dissuading other countries, allies and adversaries, from pursuing their own nuclear capabilities. Like advocates of a U.S. grand strategy of primacy, these analysts tend to argue that usable nuclear capabilities project resolve and dissuade competition, including from future proliferators attempting to blunt or match U.S. nuclear capabilities. Like advocates of primacy, proponents of a more credible and militarily effective nuclear posture tend to downplay the risk that American behavior will be misperceived by outside observers.

In contrast, skeptics of the need to procure a spectrum of flexible and modernized nuclear capabilities argue that adversaries are likely to be antagonized and even emboldened rather than cowed by nuclear capabilities that seem more usable. These analysts also maintain that nuclear weapons are inherently dangerous, and no amount of safing, security, or command and control refinements can eliminate the latent risk of escalation or accidental nuclear war. For skeptics, deterrence depends on restraint, nuclear weapons are only fit to deter nuclear attacks on the homeland, and conventional capabilities can make up for nuclear capabilities at an affordable cost. While some who hold these views also tilt in favor of global nuclear disarmament, few would quarrel with the need to invest in the existing nuclear infrastructure to keep it safe and secure.

Indeed, often lost in the many debates over the nuclear posture in Washington is the significant common ground that advocates and skeptics occupy. Both largely seek to advance the twin goals of deterrence and nonproliferation, albeit disagreeing on the relative priority afforded to each. Advocates and skeptics also disagree on the best means and ways through which to achieve these goals. In other words, the principal divide in American nuclear policy debates is over tactics and strategies rather than ends. This kernel of consensus is often missing from the prevailing discourse.

Advocates and skeptics also tend to leave unexamined a number of shared assumptions about the relationship between what the United States says and does, and what allies and adversaries say and do. Both sides assume that allies and adversaries are closely scrutinizing and reacting to shifts in U.S. declaratory and operational policy. On the contrary, scholars have struggled to establish a general relationship between the character of security guarantees and whether or not an ally still chooses to acquire its own nuclear forces. The United States often has had to rely on coercion and denial as well as persuasion to restrain the nuclear ambitions of its allies. Similarly, nuclear skeptics who argue for a greater role for conventional forces in deterrence and assurance tend to downplay strong evidence that adversaries might explore the pursuit of nuclear weapons because the United States has been willing and able to rely on overwhelming conventional power. Similarly, these skeptics argue forcefully for continued U.S. engagement and leadership in the world, while underestimating the extent to which the liberal international order continues to be underwritten by nuclear deterrence.

Analysts on both sides at times make bold and sometimes unsubstantiated assertions about the consequences and implications of their preferred approach to nuclear policy. For instance, advocates of a low-yield submarine-launched ballistic missile do not provide evidence, even from simulations and operations research, showing that Russian early warning systems could discriminate between a single SLBM and a massive counterforce attack. This leaves advocates open to attack from skeptics who cite Cold War-era findings of the difficulties and fraught tradeoffs involved in a variety of nuclear employment scenarios. For instance, multiple studies and war games have concluded that battlefield nuclear uses posed extensive hazards to American and allied servicemen and women while creating severe command and control challenges. Similarly, the history of planning for limited nuclear uses is one of contending with potentially unsolvable tradeoffs. “[Such] attacks must be effective yet at the same time recognizably limited…the command and control system must ‘endure’ so that the withheld forces can be kept under control…”

In turn, critics assert that no new nuclear capabilities are needed because current ones will suffice. But skeptics of the need for a new nuclear-tipped air-launched cruise missile, for example, often fail to address how Russian and Chinese anti-access/area-denial capabilities affect the ability of U.S. or allied fighters and bombers to deliver their nuclear payloads.

We do not mean to suggest that either side is wholly correct or incorrect, but rather that both are interpreting the same narrow body of evidence in a way that downplays the significant ambiguity inherent in nuclear decision-making. Perhaps one explanation for the remarkable continuity in U.S. nuclear policy is the need to hedge against the limits and risks of an uncertain world. The common response to ambiguity at the operational level has been to build in redundancies in forces and planning assumptions, embracing the notion that if a little deterrence is good, more is probably better.

The long-standing debate between advocates and skeptics has played out in the post-Cold War era’s four Nuclear Posture Reviews. Yet in rehearsing this debate over multiple presidential administrations, both advocates and skeptics have failed to engage with the substance of nuclear plans and policies. As a result, none of the most ambitious prescriptions in past reviews have translated into lasting changes  in operational capabilities and employment plans.

Past Nuclear Posture Reviews: Dyads, Hedges, and New Triads

The nuclear posture review process is a post-Cold War phenomenon, born out of the Clinton administration’s desire to conduct a “bottom-up review” of force structure in light of the new international environment and congressional pressure on defense budgets. Subsequent reviews were undertaken in 2001, at the start of the George W. Bush administration, and in 2009, at the start of the Obama administration. What is most striking is how little these documents ended up transforming the American nuclear posture. Every review failed to bring about major changes in the U.S. operational nuclear posture despite repeatedly averring that nuclear weapons were contributing less and less to U.S. national security goals.

Undertaken in the context of a remarkably benign international security environment, the 1994 review found that “nuclear weapons are playing a smaller role in U.S. security than at any other time in the nuclear age.” Consequently, Clinton’s bottom-up review of the Nation’s defense posture, of which the Nuclear Posture Review was a component, set forth the goal of enhancing and sustaining U.S. conventional superiority. Meanwhile, the Nuclear Posture Review called for “a much smaller nuclear arsenal,” to be achieved through “dramatic reductions.” But the document also concluded that the United States had to “hedge” against a return to nuclear competition with Russia, and called for retaining sufficient nuclear weapons to reconstitute past force levels if needed. Consequently, while the Clinton administration reduced deployments of both strategic and non-strategic nuclear weapons, the actual number of nuclear warheads in the stockpile remained more or less the same well into the 2000s. The Clinton review, moreover, retained the possibility of using nuclear weapons first in response to a chemical or biological  attack against the United States or its allies.

The George W. Bush administration also set itself a goal of dramatically recasting American nuclear strategy through the nuclear posture review process. It too failed to bring about dramatic change. The Bush Nuclear Posture Review, begun in 2001, boldly declared that the United States was replacing the Cold War nuclear triad of bombers, land-based intercontinental ballistic missiles, and sea-launched ballistic missiles with a “New Triad” comprising a mix of nuclear and non-nuclear global strike capabilities, a variety of strategic defenses including missile defense, and a defense infrastructure geared for constant and rapid innovation. Although the Bush administration’s abrogation of the Anti-Ballistic Missile treaty opened the door for new missile defense endeavors, the New Triad was never institutionalized in operational planning. Indeed, the principal drafter of the 2001 review, then Deputy Assistant Secretary of Defense for Forces Policy Keith Payne, has not reprised the framework in his subsequent work. Like the Reagan administration before it, the Bush Nuclear Posture Review failed to make strategic defenses a central component of U.S. deterrence policy.

President Barack Obama’s Nuclear Posture Review departed from its predecessors in giving significant consideration to nuclear nonproliferation, arms control, and disarmament. Yet that document also failed to realize many of its ambitions. Some of the same analysts who criticize the Trump Nuclear Posture Review today chided the Obama administration for failing to “clearly and significantly reduce the role of and numbers of nuclear weapons” in U.S. posture and policy, and for entirely preserving the configuration and operational assumptions embedded in the nuclear triad. Most notably, while calling for reducing the role of nuclear weapons and discouraging proliferation through force reductions, the Obama review also endorsed the most ambitious program of nuclear modernization in three decades.

Same as It Ever Was?

Still, it is possible that the past is not a prologue for the 2018 Nuclear Posture Review. The 2016 election demonstrated that American politics and policy are at times less predictable than many analysts presume. Like President Donald Trump’s ambitious campaign pledges, however, the review must contend with the strong tendencies toward continuity which inhere in American government. There are reasons to suspect that these will militate against dramatic changes in the nuclear posture.

There remains a large and persistent disconnect between debates in Washington and the day-to-day requirements and challenges facing nuclear operators. While political leaders and outside experts have focused on debating the role of nuclear weapons, military planners have been forced to adapt nuclear plans to meet the requirements of military effectiveness and operational reliability if deterrence fails.  Bridging this gap is the responsibility of political leaders, who bear the responsibility of harmonizing nuclear plans with national priorities and directives. However, the complexity of and need for secrecy surrounding nuclear planning, and the strong incentives for presidents and their staffs to direct their efforts elsewhere, mean that few have succeeded in doing so.


Janne E. Nolan is the Chair of the Nuclear Security Working Group, a bipartisan group of senior policy experts who promote bipartisan discourse about the benefits of nuclear deterrence and nuclear diplomacy. Currently on the international affairs faculty of the Elliott School at George Washington University, she has held senior policy positions in the Department of State and the U.S. Senate and served as an appointee of several blue ribbon commissions, including the White House Presidential Advisory Board on U.S. Arms and Technology Policy (chair), the National Defense Panel, the Department of State’s Accountability Review Board, the Panel to Assess the Ballistic Missile Threat to the U.S., and the Defense Policy Board. She is the author of nine books and many articles about U.S. national security.

Brian Radzinsky is deputy director of the Nuclear Security Working Group and a Ph.D candidate-in-residence at the Institute for Security and Conflict Studies at the George Washington University Elliott School of International Affairs.


Image: Defense Department/Kathryn Holm