What if a nuclear-armed adversary believed that U.S. conventional forces were so vulnerable that using just a handful of nuclear weapons against them would be enough to win a regional conflict? If the Department of Defense did nothing to reduce that vulnerability, wouldn’t it be inviting that sort of attack? Alternatively, what if certain U.S. conventional military operations against a nuclear-armed opponent carried a high risk of triggering nuclear use by that enemy? How should the Pentagon mitigate that risk while still achieving U.S. objectives in a regional war? These questions lie at the heart of conventional-nuclear integration, a controversial subject that Biden administration officials should consider carefully as they undertake a new Nuclear Posture Review.
Within nuclear specialist communities, there will be disagreements about those questions, and these issues are at risk of being misunderstood, distorted, and politicized. To ensure that stakeholders have a serious, rigorous debate going into the review, and to produce sound policy coming out of it, it is necessary to avoid misconceptions and mistakes about the integration of conventional and nuclear planning.
The Pentagon has not publicly offered a definition of such integration. Internally, department officials and military leaders think about the concept in several related ways. Integrating conventional and nuclear planning is actually a subset of the military’s broader pursuit of integration across land, sea, air, space, and cyberspace. In that context, the Defense Department thinks about the concept as ensuring that U.S. conventional forces can not only survive but also continue to fight during a limited nuclear attack in a regional conflict. The Pentagon combines this focus on conventional force resiliency with ensuring that credible options exist for a limited U.S. nuclear response, should the president call for them. Additionally, the concept is designed to raise awareness of how certain kinds of U.S. conventional military operations might inadvertently increase an adversary’s incentives to resort to nuclear use. Defense Department experts also consider how to deter, counter, and defeat the integration of conventional and nuclear forces by adversaries.
The current policy debate about these issues has been misleading and incomplete. To rectify that problem, and to enhance the strategic value of the Nuclear Posture Review, it is important to be clear about how conventional-nuclear integration could help reduce the U.S. military’s vulnerabilities while also helping to advance various goals of the Biden administration.
What Some Analysts Fail to Grasp About Conventional-Nuclear Integration
Precisely because there is no publicly available Defense Department definition of conventional-nuclear integration, nuclear deterrence skeptics have interpreted the concept in ways that support their views about the role nuclear weapons should play in American national security strategy. Those analysts have failed to understand a series of important points related to what convention-nuclear integration is, the challenges it addresses, and what benefits it offers to the U.S. military.
‘Sole Purpose’ Should Not Be the ‘Sole Driver’
As vice president, and again during the 2020 election campaign, President Joe Biden proposed that the United States adopt a nuclear declaratory policy of “sole purpose,” which would involve stating that the only role for American nuclear weapons is to deter nuclear use and, if necessary, respond to it. Some have suggested that a “sole purpose” policy should drive the integration of U.S. conventional and nuclear planning. That approach would risk hollowing out America’s nuclear deterrent by focusing too much on conventional forces. It would undermine the central purpose of conventional-nuclear integration, which is to reduce an adversary’s incentives to initiate nuclear use by demonstrating that the U.S. military has a balanced and integrated menu of credible nuclear and non-nuclear response options. To achieve that, the administration should pay equal attention to, and ensure consistent pacing among, all aspects of the concept — conventional, nuclear, and integration. The Defense Department should retrain conventional forces to operate on a nuclear battlefield, ensure that combatant commanders with geographic areas of responsibility are prepared to conduct limited nuclear strikes if called upon, and achieve greater planning and operational cohesion between these force elements so that no seams are left for adversaries to exploit.
Conventional-Nuclear Integration Will Not Lower the U.S. Threshold for Using Nuclear Weapons
Making sure U.S. conventional forces are not paralyzed by an adversary’s limited nuclear use does not diminish America’s natural reluctance to use nuclear weapons. In fact, having more resilient U.S. conventional forces reduces an adversary’s incentive to initiate a nuclear attack on them in the first place. U.S. readiness to conduct limited nuclear strikes in a regional conflict also reminds an adversary it will face substantial penalties for crossing the nuclear threshold. By helping to deny adversaries a clear path to victory, more closely integrated U.S. conventional and nuclear planning will bolster deterrence of regional aggression. If the U.S. military conducts such planning in a more holistic way, it will also better position itself to identify and mitigate situations in which its conventional operations might inadvertently lead to nuclear escalation by an adversary.
Integrating Conventional and Nuclear Planning Is Not Cold War Thinking
The Pentomic Division and the Davy Crockett short-range nuclear rocket were early attempts by the U.S. military to integrate conventional and nuclear weapons. No one in the U.S. government is advocating a return to such Cold War experiments and excesses. To link such anachronisms to contemporary planning and thinking, and to imply a rediscovered U.S. enthusiasm for nuclear warfighting, is wrong and misleading. Indeed, senior military leaders have repudiated this connection explicitly. Lt. Gen. Richard Clark, while serving as the Air Force’s deputy chief of staff for strategic deterrence and nuclear integration, noted that today’s conventional-nuclear integration “is different than a Cold War mentality where we had nuclear artillery, we had short-range [nuclear] rockets, where we had [nuclear] weapons that would allow us to fight tactically in a conflict.” Clark added that:
Today, really what we’re trying to prepare ourselves to do is to respond with whatever force is necessary in a nuclear environment … really the ultimate goal here is to deter. We want to raise that threshold of use of nuclear weapons, whether strategic or non-strategic … to the highest level possible.
The current wave of Pentagon interest in conventional-nuclear integration began during the Obama-Biden administration. It surfaced in the 2014 Quadrennial Defense Review as a concern that adversaries could try to escalate their way out of failed conventional aggression. Acknowledging these roots helps frame the debate for how the Biden-Harris administration can derive the most benefit from integrating conventional and nuclear planning.
The Need Is Not Based on an Inaccurate Reading of Adversary Strategy
While academics and analysts should debate the issue, America’s civilian and military officials — who have access to the most sensitive intelligence — have made clear that the threat of limited nuclear use by adversaries is real. As Clark also emphasized last year:
If you look at Russia, for example, they look at our [conventional] precision weapons, the speed and accuracy of those precision weapons and their inability to really contend with them. So they developed a strategy and a doctrine that perhaps they could use non-strategic nuclear weapons in a regional conflict to set us back on our heels, so that they could actually gain that advantage and escalate that conflict to win ultimately. It’s something again that we have not focused on but that we are starting to look at and the threat that Russia poses is driving us to do that. I think they believe that there’s a potential advantage for them [in] a limited nuclear conflict and it is very clear in their doctrine and in the capability, the non-strategic nuclear weapons that they have amassed over the years. It is evident that that’s in their planning, in their strategy, and their thought process.
American officials — who have the solemn responsibility to protect their nation and its allies — should continue to take steps to address that threat, including through appropriate integration of conventional and nuclear planning.
The U.S. Military Shouldn’t Be Discouraged From Reducing Its Vulnerability to Limited Nuclear Attacks
After decades of neglect, recent gains in joint force nuclear education, training, and doctrine development have been hard-won, but there is still much work to do to make U.S. conventional-nuclear integration an operational reality. The notion that the military could reduce its vulnerabilities in this area without setting stretch goals and exacting requirements for the services and combatant commands is unrealistic and only invites complacency. Worse, such half-hearted support for joint force integration of conventional and nuclear planning will sustain adversary interest in lowering the nuclear threshold.
Conventional-Nuclear Integration Should Not Be Politicized
Arms control advocates should resist efforts to politicize conventional-nuclear integration as a rationale to cut programs they oppose for other reasons. This politicization will discredit the concept and jeopardize the military’s ability to operationalize it over the longer term. In particular, delaying modernization of the B61-12 — the nuclear gravity bomb that has been at the heart of NATO nuclear burden-sharing for decades — under the pretext of trying to “figure out” conventional-nuclear integration will sow division and doubt within the alliance. That would be a mistake at a time when NATO solidarity is most needed to deter Russia — and it would also undermine extended deterrence, which is a top goal of the Biden administration.
The U.S. Military Should Change Mindsets
Limited nuclear use in a regional conflict could look attractive to an adversary, in part, because the U.S. military has left itself vulnerable to it. The Defense Department had de-emphasized education, training, doctrine, planning, and exercises related to surviving and operating on a nuclear battlefield in the belief that it alone would set the terms of future conflict, and could do so in ways that played to its advantages in precision conventional weaponry.
Planning by combatant commands and attitudes at all ranks aligned with these views. As the Defense Science Board noted in 2016, “Expertise in the Combatant Commands to assess and plan for U.S. conventional force operations in an adversary generated, limited nuclear environment is lacking.” This reflected a prevailing attitude that, if an enemy introduced nuclear weapons into a regional conflict, the fight would become Strategic Command’s problem. The board also found that, “General knowledge in the military regarding nuclear weapons and the environments they generate, outside of some in the strategic force cadres in the Air Force and Navy and a small group of specialists in the Army, does not exist.”
To reverse these deficiencies and reduce U.S. vulnerability to limited nuclear attacks, the Defense Department should change mindsets. Commanders with a geographic responsibility facing nuclear-armed adversaries should give greater emphasis to nuclear planning and assessment. Heavily relying on others, such as Strategic Command, to do this inhibits conventional-nuclear integration and reinforces the perception that “nuclear” warfare is someone else’s responsibility, not a routine part of geographic combatant command planning. That approach creates a seam that American adversaries might exploit — a geographic combatant command’s inattentiveness to planning and training for limited nuclear response options potentially leaves the president short-handed, which is what U.S. adversaries prefer.
The good news is that these attitudes are changing. Senior military commanders have become sensitized to the risks of limited nuclear use by adversaries, and the services are moving forward with new education, training, exercises, and concept development related to conventional-nuclear integration. Moreover, additional resources now exist within the Pentagon to help commanders with a geographic focus build up nuclear expertise within their staffs. But, the emerging mindset should be broadened and deepened. That will only happen when commanders set the tone and when top leadership holds all ranks accountable for meeting exacting conventional-nuclear integration requirements.
How Does Conventional-Nuclear Integration Align with and Further Biden Administration Priorities?
As the administration embarks on preparing the Nuclear Posture Review, it is unclear what approach it will adopt toward conventional-nuclear integration and whether administration officials might oppose it. That lack of clarity is common in the early months of a new administration. But, there are in fact several reasons why conventional-nuclear integration aligns with the major priorities the president articulated in the Interim National Security Strategic Guidance.
Conventional-Nuclear Integration Is Compatible with Reducing U.S. Reliance on Nuclear Weapons and More Constrained Declaratory Policy
Integrating conventional and nuclear planning is entirely consistent with the Biden administration’s goal of reducing reliance on nuclear weapons because it entails close scrutiny of the interaction between nuclear and non-nuclear forces. A broader array of alternatives to the use of nuclear weapons is likely to be the result.
Pentagon officials who think about conventional-nuclear integration are not considering how to increase U.S. reliance on nuclear weapons. They are not looking for new nuclear missions — they are responding to U.S. adversaries who are increasing their reliance on nuclear weapons to overcome conventional force deficiencies. The Trump-Pence administration undertook modest steps, such as downsizing the yield on some warheads carried by ballistic missile submarines, in order to show adversaries that the U.S. military had credible responses to any limited nuclear use they might attempt. This has not resulted in new U.S. nuclear weapons or missions, and American allies have accepted this posture as a necessary adjustment to ensure the credibility of extended deterrence.
It’s Integral to Rebuilding Alliances
American allies, particularly in Eastern Europe and Northeast Asia, are increasingly concerned about nuclear-backed coercion or aggression by Russia, China, and North Korea. The Biden administration’s forthcoming strategic review will likely feature close collaboration with allies to elicit their views and offer reassurances in this regard. Reaffirming, if not elevating, the U.S. commitment to counter such coercion by improving the military’s ability to stand up to threats of limited nuclear use will go far in reassuring allies. Indeed, engaging allies on conventional-nuclear integration — thereby making combined forces more resilient to limited nuclear threats — is a tangible and sensible expression of American security guarantees.
It’s Not a ‘Big-Ticket Item’
Conventional-nuclear integration is not a weapon system to be purchased. That is welcome news for a defense budget already under stress. The military will attain the necessary integration incrementally. To be sure, there are costs associated with increasing the resiliency of the joint force against limited nuclear use in a regional conflict, but they are manageable. For instance, the military estimates that making mission-critical hardware resistant to the effects of nuclear weapons, collectively referred to as hardening, adds 1 to 3 percent to its cost — if such hardening is designed into the system from the get-go. Retrofitting after the fact costs significantly more, so the services can realize savings if they prioritize nuclear survivability. During the Obama administration, the Defense Science Board strongly recommended that, “All major acquisitions be born with a nuclear survivability requirement derived from projected threat scenarios relevant to the range of missions expected for the system.” It is up to the Biden administration to see this through.
The military’s normal operating costs already cover the principal means of achieving the education, training, planning, and exercising needed for conventional-nuclear integration. Conventional forces have to re-learn what it’s like to operate under threat of nuclear attack, and the services are already moving in that direction. That comes with a new emphasis on integrating non-nuclear and nuclear forces, not necessarily additional costs.
Toward a Successful Nuclear Posture Review
The success of the Biden administration’s strategic review will depend, in part, on the degree to which myths are dispelled, threats are addressed, and goals are aligned. Conventional-nuclear integration has much to contribute in those regards — it offers the administration an affordable and responsible path to reducing U.S. reliance on nuclear weapons, deterring nuclear use in regional conflicts, and bolstering U.S. alliances. It’s time for a more-informed and better-balanced debate about U.S. nuclear strategy and the contribution of conventional-nuclear integration to it.
Gregory Giles is a senior director with Science Applications International Corporation. For the past three decades, he has been advising U.S. government clients on issues related to deterrence, nonproliferation, and the Middle East. The views expressed in this paper represent the personal views of the author and are not necessarily the views of Science Applications International Corporation, Lawrence Livermore National Laboratory, the Department of Defense, or the Department of the Air Force.