Conventional-Nuclear Integration in the Next National Defense Strategy

The Bottom Line

The next National Defense Strategy (NDS) should prioritize conventional-nuclear integration so that:

• U.S. defense and nuclear policies give precedence to deterring limited adversary aggression that is backed by threats of escalation, including across the nuclear threshold.
• Deliberate combatant command plans are designed to achieve U.S. objectives while minimizing the risk of nuclear escalation.
• Combatant commands have adaptive planning capabilities and procedures to develop courses of action that will achieve U.S. objectives should the adversary employ nuclear weapons.
• The Joint Force is prepared to conduct operations under threat of adversary nuclear employment, and if necessary, in a nuclear environment.
• The best mix of U.S. nuclear, non-nuclear, and dual-use capabilities are fielded to deter conflict and escalation.

Introduction

Many of the challenges that will confront the next NDS relate to new military technologies, ranging from maneuvering hypersonic-speed missiles to artificial intelligence and machine learning. It is just as important for the strategy to account for how major power adversaries may rely on a proven technology—nuclear weapons—to advance their interests in a conflict with the United States and its allies. For too long, the trend was to treat nuclear weapons issues as a bolted-on annex of U.S. defense planning. But now that U.S. defense strategy has recentered on preparing for high-intensity conflict with nuclear-armed adversaries, the next NDS must build on the limited progress that has been made to integrate conventional and nuclear strategy, planning, doctrine, and capabilities.

Strategy

The United States needs a strategy for fighting wars with nuclear-armed adversaries over limited objectives. Whether in a conflict with Russia or China, the United States requires a warfighting approach that allows it a chance to achieve limited objectives while deterring major escalation, including an adversary’s decision to employ nuclear weapons to terminate a conflict on terms favorable to it. Moreover, if deterrence of nuclear employment fails, the United States needs political-military options for achieving its objectives while managing the risk of further escalation. Having such a strategy, backed by effective planning, doctrine, operational concepts, and capabilities, will help deter conflict and increase the likelihood that the United States can favorably manage escalation should conflict occur.

Over the past decade, there has been a greater recognition of the threat of limited nuclear escalation by U.S. adversaries. The 2014 Quadrennial Defense Review argued for the importance of U.S. nuclear forces in “communicating to potential nuclear-armed adversaries that they cannot escalate their way out of failed conventional aggression.”¹ The 2018 Nuclear Posture Review (NPR) picked up on this theme, focusing on the need to deter limited nuclear attack by potential adversaries and achieve U.S. objectives should an adversary cross the nuclear threshold.² For the most part, concern with adversary limited nuclear employment has focused on Russia, and to a lesser extent North Korea, but officials and analysts have also suggested that China might consider nuclear escalation in extreme circumstances, despite its no-first-use pledge.³

Favorably managing escalation is sure to be a theme in the next NDS, but at least three issues will need to be debated. First, how are opponents likely to leverage an increasing number of nuclear/conventional-capable (“dual-capable”) theater range systems against the United States and its allies? These systems are clearly important to opponents’ theater campaign planning, but questions remain about how Russia and China are likely to conduct integrated nuclear-conventional operations and manipulate risk. Second, just how dire is the threat of adversary nuclear escalation? Despite an overall increase in concern about limited nuclear employment, there is debate about just how likely Russia or China would be to consider nuclear employment, and in what circumstances.⁴ Third, what is most likely to affect adversary calculations regarding nuclear employment? Some argue that the key to persuading opponents not to consider nuclear employment is to strengthen the U.S. political commitment to allies, and thus demonstrate resolve.⁵ Others maintain that supplemental, more credible nuclear retaliatory options are needed.⁶ Many views fall in between. How the next NDS answers these questions for Russia and China will affect how the Department of Defense (DoD) prioritizes conventional-nuclear integration relative to other defense strategy initiatives.

Planning

Preparing for high-intensity conflict with nuclear-armed adversaries requires improvements to U.S. combatant command planning. In the years since the Cold War, there has been a large gap between nuclear and conventional planning. U.S. European Command and Indo-Pacific Command have developed detailed operational plans for fighting conventional wars with Russia and China respectively. More recently, they have been directed to include in their operational plan development input from other combatant commands. Even so, U.S. European Command and Indo-Pacific Command have, for the most part, deferred responsibility for nuclear weapons, leaving U.S. Strategic Command to consider the deterrence of adversary nuclear use and deliberate planning for U.S. nuclear employment.⁷

The 2018 NPR directed the department to “plan, train, and exercise to integrate U.S. nuclear and non-nuclear forces to operate in the face of adversary nuclear threats and employment.”⁸ U.S. European Command, Supreme Headquarters Allied Powers Europe (NATO), and U.S. Indo-Pacific Command have begun to respond to the need to consider potential nuclear escalation in planning. Furthermore, the DoD writ large, through initiatives such as global integration and the development of a joint warfighting concept, has started to integrate planning between various regional and functional combatant commands.

Yet significant gaps remain. War plans for defeating or rolling back Russian or Chinese aggression must envision political objectives and a way of conducting operations that reduces the likelihood that an adversary will risk nuclear escalation. These plans must be seamlessly integrated among all relevant regional and functional commands, and they must include common objectives and approaches, clear responsibilities, and appropriate command and control arrangements. Planners need to understand why and when an opponent of the United States might choose to conduct nuclear strikes, and they need a thorough grasp of the challenges associated with opponents deploying increasing numbers of dual-capable theater range strike capabilities, collocating conventional and nuclear forces, and integrating conventional and nuclear command and control.

In addition, the United States requires an improved planning capability to develop courses of action that will achieve its objectives should an opponent employ nuclear weapons. How can the joint force continue prosecuting its campaign while attempting to deter further nuclear employment by an adversary? The DoD can begin to answer this question in the deliberate planning process but must also have a robust adaptive planning capability that can quickly develop options appropriate to specific circumstances. The heightened potential of further nuclear escalation will make developing and implementing any course of action extremely complicated, even more so if the United States chooses to include in an ongoing conventional campaign the planning and execution of limited nuclear strikes.⁹ The department should grapple with where certain deliberate and adaptive planning capabilities should primarily reside, and with how to effectively coordinate among senior civilian leaders, combatant commands, and allies during a conflict.¹⁰

Doctrine

The United States must also ensure that it can conduct operations under threat of adversary nuclear employment and, if necessary, in a nuclear environment. An opponent is more likely to choose nuclear escalation if it perceives that it can significantly degrade the effectiveness of U.S. conventional operations. Unfortunately, however, the joint force is not adequately prepared or equipped to operate effectively in a nuclear environment.¹¹ Cold War operational concepts for dispersal to reduce vulnerability to nuclear strikes have waned, as have unit standards for operating through radiation and electromagnetic pulse effects. A generation of military officers has fought in wars in which they never had to consider adversary employment of nuclear weapons.

The next NDS should ensure that joint doctrine supports effective operations under threat of nuclear employment. In addition to mandating that critical military platforms, weapons, and equipment meet hardening standards, the Department must prepare to operate using dispersed bases, logistics hubs, and formations, and it must train key conventional units to fight through nuclear effects. The services have begun developing their own concepts for conventional-nuclear integration, but these visions must be finalized, merged into joint doctrine, and then realized through procurement standards, professional military education, and training and exercise requirements.

As a general objective, preparing the joint force to operate under the threat of nuclear employment is likely to be uncontroversial; however, there is certain to be debate over nuclear hardening standards, given the additional expense, and whether dispersal and other measures can adequately address survivability concerns. In addition, conventionally oriented planners may resist making changes to operational concepts that will reduce efficiency and effectiveness should the adversary not employ nuclear weapons. There will always be a balance and difficult tradeoffs, but defense strategists should acknowledge that if U.S. conventional operations are perceived as vulnerable to nuclear strikes, there is a greater likelihood that an opponent will opt for nuclear escalation.

Capabilities

A final aspect of conventional-nuclear integration is finding the best mix of nuclear, non-nuclear, and dual-use capabilities to deter conflict and escalation. The potential for adversary nuclear escalation is a subset of a larger problem: those who oppose the United States have studied its way of war and developed multi-domain military capabilities of their own to deter and, if necessary, defeat U.S. intervention in a regional conflict. Russia and China are building capabilities that may allow them to take advantage of surprise, along with a favorable local balance, to impose their will on U.S. allies. With cyber weapons, counterspace capabilities, and long-range conventional strike, they have additional options for imposing costs on the United States and manipulating the risk of escalation. Dual-capable systems that can be mated with nuclear weapons are also part of these plans, and the option to conduct theater nuclear strikes is available to their political leaders. The United States, to defend its interests effectively, needs capabilities that can blunt adversary aggression against U.S. allies, and it needs its own credible options for threatening retaliation and escalation to deter adversary escalation.

Balancing investment among U.S. conventional, nuclear, and dual-use capabilities is an area in which there is likely to be significant debate during the development of the next NDS. According to one view, the DoD should deprioritize investment in nuclear weapons and focus instead on conventional contact- and blunt-layer forces that are most likely to deny a rapid fait accompli.¹² Many who subscribe to this view think that the threat of adversary nuclear escalation is overblown, and that additional nuclear capabilities are more likely to cause instability than to strengthen deterrence. Others acknowledge the threat of adversary nuclear escalation but argue that denying the fait accompli is nonetheless the most effective tool for preventing escalation. Yet another view holds that deterring adversary nuclear escalation in a conflict requires a range of response options, including a variety of delivery platforms and yields, along with different ways of penetrating an opponent’s defenses, and that little money will be saved by trimming investment in nuclear weapons.¹³ According to this view, those who oppose the United States are less likely to initiate and escalate conflicts if they are less confident in their options for nuclear escalation.

In addition to continuing to recapitalize the nuclear triad of intercontinental ballistic missiles, ballistic missile submarines, and strategic bombers, the Donald Trump administration has pursued two supplemental capabilities: a limited number of low-yield warheads on ballistic missile submarines, which have now been deployed; and a new nuclear-capable sea-launched cruise missile (SLCM), which is undergoing an analysis of alternatives. With defense budgets likely to be tight, these decisions, particularly the pursuit of a nuclear SLCM, will be reviewed. The department will be forced to prioritize among major acquisition programs, and it may have to choose between marginal increases in conventional or nuclear deterrence. Deploying a nuclear-capable SLCM, for example, may cause adversaries to be more hesitant to cross the nuclear threshold, but this decision could come at the cost of tying up platforms, or missile or torpedo tubes, that are needed for conventional warfighting. On the other hand, forgoing the deployment of credible nonstrategic nuclear capabilities may cause opponents to be more confident in their ability to manage escalation, thus increasing the likelihood of adversary nuclear strikes in a regional conflict.

Recommendations

The next NDS should prioritize conventional-nuclear integration as follows:

Strategy

• Refine the U.S. approach for winning conventional wars against nuclear-armed adversaries while favorably managing the risk of nuclear escalation.

Planning

• Ensure that the operational plans for conflict with Russia and China are integrated among all relevant regional and functional commands and designed to deter nuclear escalation.
• Improve the ability of combatant commands to adaptively develop courses of action to achieve U.S. objectives should an adversary employ nuclear weapons.

Doctrine

• Establish joint doctrine for conventional-nuclear integration that sets standards for the content of professional military education and training and exercises.
• Develop operational concepts that include dispersed bases, logistics hubs, and formations to reduce vulnerability to nuclear strikes.
• Implement nuclear hardening standards on critical military platforms, weapons, and equipment.

Capabilities

• Field the appropriate mix of nuclear, non-nuclear, and dual-use capabilities to deter conflict and escalation.

Conclusion

The next administration has an opportunity to build on the progress of the 2018 NDS by conducting an integrated deterrence and defense review. In this process, the next defense strategy should focus on developing concepts and capabilities for winning regional wars with nuclear-armed adversaries, while at the same time reducing the likelihood of escalation. These concepts should drive the conventional-nuclear integration that is needed in planning, doctrine, and capabilities.

About the Author

John K. Warden is a Research Staff Member in the Strategy, Forces, and Resources Division at the Institute for Defense Analyses (IDA), where he contributes to studies and analyses in support of the Office of the Secretary of Defense, the Joint Staff, the combatant commands, and other national security agencies. The views, opinions, and findings expressed should not be construed as representing the official position of either the Department of Defense or IDA.

Learn More

From July to December 2020, CNAS will release new papers every week on the tough issues the next NDS should tackle. The goal of this project is to provide intellectual capital to the drafters of the 2022 NDS, focusing specifically on unfinished business from the past several defense strategies and areas where change is necessary but difficult.