To Deter and Assure: A US Nuclear Posture Tailored for Three Theaters

The United States confronts an unprecedented—and unexpected—geopolitical challenge. For the first time in the nuclear age, America faces not one but two nuclear-armed peer adversaries in China and Russia. Beijing has shocked Washington by undertaking a massive nuclear buildup and will soon join Moscow as a nuclear power of equal standing with Washington. The Kremlin, meanwhile, has defied America’s expectations by violating arms control agreements, growing a large theater nuclear force, and launching brutal wars against its neighbors. And this is to say nothing of a nuclear-armed North Korea conducting provocative flight tests of ballistic missiles and an Iran poised to cross the nuclear threshold. Put simply, when US planners established nuclear force requirements more than a decade ago, they did not anticipate the threats confronting the United States today.

Flawed assumptions have thus saddled the United States with a nuclear arsenal lacking the capacity and capability to compete against two nuclear peers and lesser regional threats. This “two-peer-plus” security environment demands a US nuclear posture that can deter across multiple theaters and, should deterrence fail in one or more of them, achieve wartime objectives while dissuading opportunistic aggression elsewhere. Washington can no longer afford to wish away mounting nuclear threats in the Asia-Pacific, Europe, and the Middle East—especially since these threats have coalesced into an autocratic axis bent on breaking the US-led liberal order. Fortunately, Washington can afford a nuclear deterrent that underwrites a multi-theater posture and assures far-flung allies of the US security guarantee. And it can do so without weakening America’s overall deterrence and turning the conventional posture into the bill payer for nuclear modernization.

Deterring adversaries and assuring allies across geographically dispersed regions is by no means a novel challenge for US defense planners. But the emerging two-peer-plus threat environment undoubtedly intensifies this dilemma and calls for tailored adjustments to the US nuclear posture. While the nature of deterrence transcends time, space, and the number of adversaries—peer or otherwise—its character must reflect the particular players; their distinctive values, theories of victory, and geographic orientations; and the balance of resolve and military capability among them.

This chapter develops a US nuclear posture fit for the unique attributes of today’s evolving security environment. First, I examine how flawed planning assumptions caused the strategy-resource mismatch the US nuclear posture finds itself in today. Second, to close the gap between US nuclear strategy and the resources available to execute it, I establish new force requirements tailored to the distinctive coercive attributes of America’s adversaries. Finally, I lay out a US nuclear posture fit to deter threats and assure allies across three theaters. Meeting the security challenges of today and tomorrow will require a nuclear posture with enhanced strike capacity, selectivity, and flexibility.

Misreading the Room

Flawed assumptions and misguided expectations have left the United States ill prepared for today’s rapidly changing nuclear threat environment. In 2010, the Obama administration’s Nuclear Posture Review identified “nuclear terrorism” as the “most immediate and extreme danger” facing the United States—and forecast that it would remain so in the long run.¹ This assessment appeared eminently sensible at the time, with the country devoting enormous resources to the global war on terror. It also aligned with a long-standing bipartisan push to adjust the US military posture to the reality that the Soviet Union, America’s only nuclear-peer adversary, had collapsed. The immediate post–Cold War security landscape was thus a far cry from that of the 1980s, when the United States confronted a hostile superpower armed to the teeth with some 33,000 nuclear weapons. Accordingly, Washington treated the relatively benign security environment of the early 21st century as an opportunity to reduce reliance on nuclear deterrence.

This optimistic threat forecast, however, proved more fantasy than reality. Even as the United States slashed its nuclear arsenal, other states refused to act in good faith and follow suit. Consequently, the existing US nuclear posture—and the ongoing modernization program and weapons industrial base that supports it—now finds itself behind the curve of a threat environment that more closely resembles the 1980s Cold War than what planners had anticipated and set force requirements to address.

Nuclear Fantasy. In the Obama administration’s early years, America’s only nuclear peer, Russia, was deemed a reliable partner on a host of security initiatives, including President Barack Obama’s “commitment to seek the peace and security of a world without nuclear weapons.”² US defense planners designated China as a lesser-included nuclear power that harbored no ambition to join the United States and Russia as a nuclear equal. And though North Korea had successfully tested an atomic device in 2006 and Iran was researching and developing the technical means to follow suit, Washington treated both states as problems to be managed. US officials believed a robust diplomatic campaign, in partnership with Moscow and Beijing, would roll back or tame Pyongyang’s and Tehran’s nuclear ambitions.

Senior Obama administration officials thus anticipated—and set force requirements for—a relatively benign nuclear threat environment for the 2010s and beyond. Terrorism and proliferation would remain the defining challenges of the era. And great-power nuclear relations would remain a matter of arms control and disarmament—not nuclear deterrence. Having perceived “fundamental changes” in security affairs and the “easing of Cold War rivalries,” US defense planners moved confidently to reduce reliance on nuclear weapons and concentrate instead on America’s “unrivaled” precision strike conventional capabilities.³ And all the better for it, since Obama had challenged the planners “to put an end to Cold War thinking” and set an example for Russia and China to follow.⁴

The Obama administration believed its superior conventional strike capabilities would allow the United States, in partnership with Russia, to slash strategic nuclear force levels dramatically. In April 2010, Obama signed the New Strategic Arms Reduction Treaty (New START) with Moscow, which limited both signatories to 1,550 deployed strategic warheads carried on no more than 700 delivery systems.⁵ This marked a 30 percent reduction in accountable warheads from the force ceiling of 2,200 warheads the George W. Bush administration had established with Russia in 2002.⁶ Indeed, New START represented the logical next step in a long-standing bipartisan campaign to pull down America’s deployed warheads from the heights of a strategic posture that had, in the late 1980s, peaked at some 13,600 weapons. As Bush declared in a 2001 address at National Defense University, the United States would “change the size, the composition, the character of [its] nuclear forces in a way that reflects the reality that the Cold War is over.” “Today’s Russia is not yesterday’s Soviet Union,” he explained. And his administration was “committed to achieving a credible deterrent with the lowest possible number of nuclear weapons.”⁷

For the Obama administration, New START established that number—or at least the lowest possible number acceptable to Congress. But in exchange for Senate ratification of the treaty, the administration acceded to calls for recapitalizing all three legs of the nuclear triad. It established a modest program to replace America’s Cold War–era strategic bombers, air-launched cruise missiles (ALCMs), land-based intercontinental ballistic missiles (ICBMs), and ballistic missile submarines (SSBNs) with modernized versions of themselves. The United States would also pursue life-extension programs for its suite of aging warheads. Though this like-for-like modernization effort was not one of capacity (next-generation Columbia-class submarines, for example, are set to come online in fewer numbers and with markedly fewer missile launchers than today’s Ohio-class boats),⁸ it was deemed sufficient for a tranquil environment in which the only nuclear peer in sight was considered a reliable partner.

Indeed, the Obama administration’s decision to extend the life of America’s aging warheads rather than develop new ones was taken in part to perpetuate the benign security environment of the early 21st century. Every post–Cold War US administration had feared that developing novel nuclear weapons might provoke minor powers like China to undertake what Secretary of Defense Donald Rumsfeld had characterized as a “sprint toward parity” with the United States.⁹ Thus, with no acute nuclear-peer adversary on the horizon, successive administrations had deferred or canceled the modernization of nuclear weapons and delivery systems that were decades past their service life.

As a result, the US nuclear weapons industrial base atrophied to such an extent that it was ill prepared to service Obama’s modernization program.¹⁰ Nevertheless, America’s decayed nuclear production infrastructure—and its modernization program quickly falling behind schedule—hardly seemed cause for concern in such a benign setting. These were, after all, the heady days of Obama’s Prague Agenda, when many believed a nuclear-free world was within reach—if only Washington could muster the courage and discipline to lead the world down the path to disarmament.

Nuclear Reality. Alas, China, North Korea, and Russia were unwilling to follow the United States anywhere—least of all to nuclear zero. For these three despotic regimes harboring revisionist intentions, Cold War–style thinking about nuclear weapons remained very much alive.

Vladimir Putin’s Russia proved immune to Bush’s vision of a democratic post-Soviet state “at peace with itself and its neighbors.”¹¹ And following its 2008 invasion of Georgia, the Kremlin exploited Obama’s attempted “reset” by launching a brutal war in Ukraine that continues to this day.¹² As of this writing, Russia has built up a massive theater-range nuclear arsenal that dwarfs its American counterpart, and it has nearly completed a generational effort to modernize all three legs of its nuclear triad while developing a suite of “exotic” delivery systems.¹³ Together, these new force capabilities have shielded Russia’s ongoing war in Ukraine from a more forward-leaning American response. The Kremlin’s incessant nuclear saber-rattling has successfully constrained Western assistance to Kyiv and, in effect, transformed the Russian homeland into a sanctuary.

China, for its part, refused to oblige the United States and instead embarked on Rumsfeld’s feared “sprint” toward parity (which the US intelligence community projects to be on pace to match, if not exceed, America’s deployed nuclear arsenal by 2035).¹⁴ Analogous to Russia’s nuclear-backed aggression in Europe, China’s stunning nuclear breakout has provided cover for Beijing’s ongoing “short-of-war coercion” campaign in the western Pacific, which seeks to dissolve America’s forward position in East Asia.¹⁵ China now boasts vastly more land-based, nuclear-capable intercontinental and theater-range missile launchers than the United States.¹⁶ And America’s Asia-Pacific allies and partners are increasingly concerned that, as the US homeland grows more vulnerable to nuclear coercion, Washington will become risk averse in defending the regional status quo. That the United States retired its only regional nuclear response option—the Tomahawk Land Attack Missile–Nuclear (TLAM-N)—even as China fielded a massive theater capability of its own has exacerbated allied concerns about the US nuclear umbrella.¹⁷

As for North Korea, Pyongyang skirted—and with Russian and Chinese assistance, eventually wiggled its way out from under—an international sanctions regime to develop some 50 warheads and counting and a suite of nuclear-capable missile systems in various stages of development.¹⁸ And as Pyongyang’s arsenal and the reach of its missiles have grown, so has its willingness to conduct aggressive provocations along its frontier.¹⁹ South Korea in turn is increasingly anxious about America’s extended deterrence guarantee. Seoul’s anxiety is such that it has even floated the idea of developing an independent nuclear arsenal to hedge against an American retreat from the Korean Peninsula.²⁰

Iran, meanwhile, has been knocking on the door of this nuclear-armed autocratic club—no doubt perceiving security benefits in defying Washington and gaining membership. Though it has so far refrained from crossing the nuclear threshold, Iran’s recent missile exchanges with Israel and the collapse of its Axis of Resistance have exposed the glaring weakness of Tehran’s regional position—and therefore might incentivize it to bolt for the bomb. Iran is already coordinating with China, North Korea, and Russia to undermine the US-led liberal order through conventional means.²¹ Tehran may soon calculate that membership in this deepening axis of aggression lends it cover to safely cross the nuclear finish line and shore up its weakened deterrence.

The United States thus finds itself in a growing mismatch between its deterrence strategy and the resources available to execute it. Its updated 2024 nuclear weapons employment policy calls for a strategic posture “able to deter Russia, the PRC [People’s Republic of China], and the DPRK [Democratic People’s Republic of Korea] simultaneously in peacetime, crisis, and conflict.” (Emphasis added.) And to fulfill this mission, it set a requirement for a strike capacity and capability “to hold at risk what [these] adversaries value most”—including, to the extent practicable, their expanding nuclear forces.²² But America’s existing force posture (featuring 400 Minuteman III ICBMs, 14 Ohio-class SSBNs carrying 240 Trident D5 sea-launched ballistic missiles, 19 B-2 stealth bombers, 46 B-52H standoff bombers, and 528 ALCMs) was not sized and shaped to carry out this job. Nor was its like-for-like replacement program (featuring 400 Sentinel ICBMs, 12 Columbia-class SSBNs, 100 B-21 stealth bombers, and 1,087 Long-Range Standoff cruise missiles) designed to hold at risk multiple peer adversaries simultaneously. A simple quantitative assessment of the changing threat environment thus makes plain that the current program of record cannot sufficiently cover rapidly expanding target sets in Asia and Europe.

Targeting arithmetic alone, however, constitutes an incomplete force-sizing and force-shaping construct. To deter adversaries and assure allies across multiple theaters, the United States must do more than simply narrow the widening gap between strike capability and target sets. It must also tailor capability more closely to its adversaries’ distinctive approaches to nuclear weapons and its allies’ growing concerns. Thus, to establish an adequate force-planning construct that redresses America’s strategy-resource mismatch, the United States should first appraise its adversaries’ “national styles” in nuclear strategy—and their impact on US and allied security interests and capabilities.²³

Setting Requirements

China, North Korea, and Russia have coercive national styles in nuclear strategy. They have demonstrated a willingness to exploit America’s mistaken planning assumptions by expanding their arsenals and employing nuclear-backed coercion to support their revisionist agendas. And they are all leveraging America’s comparative restraint at the strategic and theater nuclear levels, at which Moscow especially has rattled the nuclear saber to paralyze NATO.

Thus, to adjust the US nuclear posture to the two-peer-plus environment, planners must tailor force requirements to distinctive adversaries and their coercive impact on American interests and allied concerns. Since deterrence threats and assurance pledges are a state of mind more than a rational science, US planners must calibrate force requirements to the peculiar adversary and allied styles of deterrence.

“Deterrence à la Russe.” The Russian way of nuclear deterrence is more forward leaning than the American national style. It encompasses the US conception of deterrence (threats to dissuade an adversary from taking a particular course of action) and what American strategic thought treats distinctly as “compellence” (threatening or actually employing nuclear weapons to compel a change in adversary behavior).²⁴ “Deterrence à la Russe” thus spans activities in peacetime competition and extends through all phases of armed conflict.²⁵ And it has profound implications for US nuclear planning.

The Kremlin, for instance, believes its way of deterrence has succeeded in Ukraine, forestalling direct NATO intervention and slowing—in select cases, even preventing—Western arms deliveries to Kyiv. Thus, US force planners would be wise to assume that even if the Russo-Ukraine war stops, Russian threats to employ nuclear weapons will not. As the security analyst Dmitry Adamsky makes clear, nuclear coercion embodies Russia’s new normal. And it will likely remain a central feature of Kremlin statecraft in the long run, given the decimation of Russia’s professional military in Ukraine.²⁶

US nuclear planners should set force requirements on the basis that the Kremlin to a great extent considers its war against Ukraine a deterrence success. They should also recognize that Russia’s new normal means the Kremlin might consider limited nuclear employment an asymmetric advantage in a future conflict with NATO. Deterrence à la Russe certainly lends itself to that kind of thinking. Moreover, Russia’s conventional power has received a thrashing in Ukraine. And its massive theater nuclear buildup vis-à-vis America’s one-sided nuclear restraint represents one of the few areas—if not the only area—of the NATO-Russia military balance in which the Kremlin holds a clear advantage. In the years ahead, then, Russia might be tempted to run risks at lower levels of conflict for two reasons: The Kremlin believes Russia’s geographic proximity to NATO’s central region or northern flank opens up an opportunity to snatch territory in a conventional fait accompli, and the Kremlin believes that even if NATO mobilizes in time to stymie such a conventional assault, Russia could still escalate its way to victory via theater nuclear employment.

NATO allies like Poland and Finland are sensitive to Russia’s theater nuclear advantage—so much so that both have expressed interest in playing a greater role in the alliance’s nuclear mission.²⁷ Indeed, the Poles’ fervor to join NATO’s nuclear-sharing program betrays how the alliance has failed to adjust to Russia’s theater buildup and NATO’s changing post–Cold War geography. For frontline members like Poland and Finland, which joined NATO following the Warsaw Pact’s demise, a future in which Russia attempts to escalate its way to victory is very real. Accordingly, they value forward-deployed US nuclear weapons far more than do Washington and the other NATO members whose borders do not rim the Russian threat. And they are increasingly unsatisfied with the hundred or so US gravity bombs—and the dual-capable fighter aircraft certified to carry them—that are based farther afield in Belgium, Germany, Italy, the Netherlands, and Turkey. Thus, to reassure anxious allies and deter Russia from exploiting its theater nuclear advantage, Washington must diversify its regional nuclear options and reconsider its basing arrangements. Poland represents NATO’s new center of gravity, and US officials should lead the alliance in integrating Warsaw (and, if interested, Helsinki) into its nuclear mission.

US planners should also reset force requirements on the assumption that Russia will be tempted to run risks at the theater level if the Kremlin senses Washington is vulnerable to coercion at the strategic nuclear level. Russian preparations to bring online the new “superheavy” RS-28 Sarmat ICBM, capable of carrying up to 10 warheads and threatening America’s geographically dispersed missile silos, are certainly an unwelcome development. However, the Sarmat alone will be insufficient to overturn the strategic balance. Alongside the US triad’s land-based ICBMs, the United States maintains a highly survivable fleet of 14 Ohio-class strategic missile submarines—set to be replaced by 12 next-generation Columbia-class boats starting in 2030. And America’s airborne leg of 19 B-2 stealth bombers and 46 B-52H standoff bombers provides further insurance.

But the existing US triad and modernization program was designed to maintain strategic- and theater-level deterrence with only the Russian threat in mind. US planners did not anticipate China ditching its long-held minimum deterrent—to say nothing of a peer nuclear China with a coercive national style on par with Russia’s.

Deterrence with Chinese Characteristics. China’s national style in nuclear strategy diverges sharply from that of the United States. The Chinese way of deterrence, or weishe, entails dissuading the adversary from taking actions harmful to Beijing and compelling actions beneficial to Beijing.²⁸ Leading Chinese defense intellectuals now routinely depict China’s expanding nuclear arsenal as a trump card to forestall or reverse US intervention in the western Pacific.²⁹ And Chinese military writings frequently treat the modernization of nuclear weaponry as “an important guarantee for achieving control of the enemy without fighting.”³⁰

Perhaps it is unsurprising, then, that China’s massive nuclear buildup over the past five years has coincided with Beijing ramping up its short-of-war coercion campaign to drive a wedge between Washington and its allies in the Asia-Pacific. Almost daily, China’s air and naval forces encroach on the airspace and territorial waters of America’s regional partners in a bid to revise the regional order. Correlation, of course, is not causation. But prudence calls for US planners to assume Beijing views its expanding nuclear arsenal as a coercive shield under which it can transform the western Pacific into a Chinese lake. Consider that even as a weak nuclear power in the immediate post–Cold War era, Beijing was willing to engage in nuclear coercion during the Third Taiwan Strait Crisis in 1996. At the height of that crisis, Chinese officials reportedly threatened to annihilate Los Angeles in a futile bid to deter US carrier strike groups from entering the region in support of Taipei.³¹ That Beijing is no longer a lesser-included nuclear power will impose new demands on US force requirements—at the strategic and theater levels—to maintain America’s forward position in the Asia-Pacific.

At the theater level, US planners should set force requirements on the assumption that China is already leveraging its improved regional nuclear capabilities to break America’s alliances. To deter and assure against this threat, the US theater nuclear posture must signal to Beijing and America’s allies that China cannot revise the regional status quo via nuclear-backed coercion or the limited employment of nuclear arms. Given China’s rapid buildup of theater nuclear delivery systems, this force requirement will present an imposing challenge to US planners.

Beijing now has in spades what it lacked for theater striking power in 1996—a problem exacerbated by America’s decision to retire the TLAM-N in 2010. Beijing boasts a suite of nuclear-capable ballistic missile systems that can hold targets at risk across the entire western Pacific. The US military hub on Guam, which enables the projection of power into the Asia-Pacific rimland, is particularly vulnerable to nuclear attack by the intermediate-range DF-26 ballistic missile. And as in Europe, America’s Asian allies are apprehensive about the dramatic shift in the theater nuclear balance. No less than Japan’s prime minister, Shigeru Ishiba, has expressed concern that the two-peer-plus threat will make “the US extended deterrence in the region . . . no longer function.”³²

American planners should reintroduce a theater-range nuclear system that has an enduring presence and the survivability to signal to allies and Beijing that US nuclear forces remain coupled to the region. Given the two-peer threat, the United States does not have the option to swing dual-capable fighter aircraft from Europe. And given the politics surrounding nuclear weapons in the western Pacific—Japan in particular—the US basing system in the region lacks the infrastructure to host nuclear weapons. A seaborne nuclear option thus offers a promising alternative to ground-based systems—all the more so because the Asia-Pacific is primarily a maritime theater.

At the strategic level, US planners should set force requirements on the assumption that a weak American triad would tempt China to run risks at the theater level. Washington must convince Beijing that if it attempts to escalate its way out of a failing regional war by employing strategic nuclear forces, America’s triad has the capacity to absorb a large-scale attack and still inflict unacceptable damage in retaliation. This planning criterion is what makes Russia’s Sarmat ICBM, in combination with China’s strategic breakout, a challenge for US nuclear planning. China’s rapid buildup of intercontinental missile launchers alone has blown past America’s 400 operational ICBM silos. And Beijing’s estimated 550 ICBM launchers, split between silos and more survivable road-mobile platforms, will soon house missiles carrying multiple warheads that can hold America’s dispersed missile silos at risk.³³

Thus, between China’s and Russia’s ICBM capabilities, the existing and planned US ICBM fleet will fall under increasing strain over the next 10 years—especially if Beijing and Moscow engage in a coordinated attack. The prospect that any war with China—whether on its own or in combination with Russia—will be protracted only adds to this burden.³⁴ Prudence calls for US planners to assume strategic submarines and bombers will suffer losses and technical failures in an extended fight.

At the strategic level of deterrence, then, the US requires more capacity and capability to absorb a massive Sino-Russian attack and then inflict catastrophic damage on targets the offending parties value most. Yet America’s program of record was sized and shaped to hold at risk just a single nuclear peer. Though the probability of Beijing and Moscow coordinating with each other to cripple the US ICBM fleet is low, strategic deterrence is of such importance to America’s global military posture that planners must prepare for this worst-case scenario. The projection of US conventional military power into the Asia-Pacific, Europe, and the Middle East depends entirely on strategic deterrence holding. And above all else, the only existential military threat to the US homeland is that of a large-scale nuclear attack.

Given the stakes and Russia’s and China’s coercive national styles, the strategic level of deterrence would be an unwise place for US planners to tolerate greater risk. Moreover, an assessment of the threats emerging in northeast Asia and the Middle East makes clear the United States should shore up its strategic deterrence so it can project power into these regions.

Deterrence of the Lesser Included. Though North Korea—and Iran, if it goes nuclear—will remain a lesser-included threat, Pyongyang’s habits of coercion will stress the mismatch between America’s nuclear strategy, strike capability, and assurance guarantees. If Washington hopes to deter North Korea and keep South Korea under its nuclear umbrella, US force planners need to reintroduce flexible and selective attack options to northeast Asia.

In January 2021, Kim Jong Un unveiled plans to develop both “ultra-large” and “smaller and lighter” tactical nuclear weapons. Pyongyang has since conducted a seemingly endless parade of test flights of short-range ballistic missiles capable of delivering such tactical weaponry.³⁵ The US Defense Intelligence Agency recently assessed that these developments signal the regime’s shift from focusing entirely on deterrence to a nuclear posture capable of managing escalation and terminating hostilities quickly should a conflict break out on the Korean Peninsula.³⁶

Pyongyang has also paired its development of more advanced tactical nuclear weapons with incendiary rhetoric about its ability to hold the US homeland at risk of nuclear attack. North Korea’s growing intercontinental missile arsenal has raised understandable alarm in South Korea that Pyongyang has weakened, if not neutralized, the United States’ extended deterrence guarantee.³⁷ South Korea’s president, Yoon Suk Yeol, has warned that if the situation “gets worse . . . our country will introduce tactical nuclear weapons or build them on our own.”³⁸ That Pyongyang and Beijing have lent critical technical assistance to Tehran’s ballistic missile program has raised similar concerns in the Middle East about Washington’s staying power in the Persian Gulf—in no small part due to the specter of a nuclear-armed Iran that looms on the horizon.³⁹

Thus, US defense planners must tailor nuclear force requirements to growing allied concerns about the US extended deterrence guarantee in northeast Asia. Moreover, since the decisions made today will determine the US nuclear posture of the 2080s (given the long lead times and lifespans of such weapons systems), planners should also factor in the prospect of a nuclear-armed Iran. Pyongyang and Tehran will, in all likelihood, remain lesser-included threats. But their respective positions on Russia’s and China’s peripheries reinforce that the US nuclear posture requires more selective and flexible response options.

For example, responding to a large-scale North Korean nuclear attack on South Korea with even a limited ICBM or submarine-launched ballistic missile (SLBM) strike would raise concerns in Moscow and Beijing about Washington’s intended target. This is especially the case because the United States might find itself engaged in simultaneous conflicts with North Korea and one or both of America’s great-power rivals. Washington thus requires a menu of more selective and flexible options, with flight profiles and azimuths that Moscow and Beijing can clearly distinguish from the ballistic trajectories of strategic missiles. This demand suggests that reintroducing a theater-range cruise missile to the Asia-Pacific would pay dividends for reasons beyond deterring China and Russia. Similarly, US planners should ensure that America’s strategic bomber fleet—the most selective and flexible attack option in the existing US arsenal—has enough slack to penetrate the vast Eurasian periphery. To deter and assure against coercion in multiple theaters, the US nuclear posture will require greater strike capacity, selectivity, and flexibility.

Conclusion: A Three-Theater Nuclear Posture

The discussion thus far has demonstrated that the existing US nuclear posture and modernization program are tailored to a benign threat environment that no longer exists. Russia has reverted to Soviet form, engaging in nuclear coercion and violating arms control agreements by building up a massive theater-range arsenal and denying Washington its right to inspect Russian nuclear sites under the New START provisions. China, meanwhile, has unexpectedly ditched its minimum deterrent and joined Russia as a peer nuclear adversary, building up at both the strategic and theater levels. And although North Korea (and possibly Iran) will remain a lesser-included nuclear threat, Pyongyang has sown doubt about America’s credibility as a security partner.

The United States therefore finds itself in a mismatch between its nuclear strategy and the resources available to execute it. The analysis so far has treated America’s existing nuclear weapons employment policy—targeting what the adversary values most (i.e., its political leadership, selected portions of its nuclear and conventional forces, and its war-supporting industries)—as entirely appropriate for the two-peer-plus environment. The analysis has also recognized that US planners must close the strategy-resource gap in such a way as to address the coercive national styles of America’s adversaries. Here, it is worth noting that for the United States to fulfill existing policy, its nuclear force posture does not require a strike capacity that equals the combined arsenals of its nuclear-armed peer competitors.

Matching China and Russia on a weapon-for-weapon basis would be irresponsible and entirely unnecessary. US planners should instead tailor nuclear forces to adversary coercive styles rather than narrowly focus on target sets alone. If the United States were to engage in a quantitative arms race, it would cede the initiative to its great-power rivals and steer vital resources away from rebuilding the Navy and other critical conventional capabilities. There is, after all, a certain synergy between nuclear and conventional deterrence. One cannot operate effectively without the other. And if one became the bill payer for the other’s reinforcement, America’s overall deterrence would be weakened. Defense planners must ensure that growing and diversifying the nuclear force structure does not starve the conventional posture of precious resources.

The preceding analysis also suggests two force-planning objectives that will resolve the strategy-resource mismatch in a coercive two-peer-plus threat environment. These planning objectives entail (1) sizing and shaping regional nuclear forces to convey to adversaries that any attempt to escalate their way to victory at the theater level is futile and (2) sizing and shaping strategic nuclear forces to convince peer adversaries that they cannot escalate their way out of a failing theater-level war by coercing Washington into submission at the strategic level. These planning objectives also dovetail with the imperative to reassure allies that US nuclear forces remain coupled to their defense.

To assess the extent to which these planning objectives have been met, the analysis has suggested looking for three areas of improvement: (1) increased strike capacity at the strategic and theater levels in Europe and Asia, (2) greater selectivity in the form of an expanded strategic bomber fleet and an expanded theater nuclear arsenal in Europe and Asia, and (3) greater flexibility in the form of more diverse and enduring regional response options in Europe and Asia.

Expanding the nuclear force structure in certain areas (e.g., the airborne and sea-based legs of the triad) will be costly. These are highly complex delivery systems, and the atrophied state of the weapons production complex throws an additional hurdle into the equation. Nevertheless, as many of the chapters in this volume demonstrate, the US economy can ramp up and sustain higher levels of defense spending to support a modest nuclear expansion that does not starve conventional capabilities. Given the mounting threats the country faces, the nuclear balance would be an unwise place for Washington to accept greater risks.

What follows, then, is a proposal for a nuclear posture sized and shaped to meet the above force-planning standards and, ultimately, strengthen the country’s overall deterrence. The first part concentrates on the immediate steps that can be taken at the strategic level and the longer-term measures that should be adopted or studied. The next part treats the theater-level of deterrence in a similar fashion, prescribing steps that should be taken or studied in both the near and long term.

Strategic Nuclear Posture. Given US strategic forces’ vulnerability to a coordinated Sino-Russian attack in a protracted war, the US nuclear triad requires an expanded strike capacity across the board. Each leg of the triad provides unique and complementary attributes that make the whole greater than the sum of its parts. ICBMs are America’s most responsive and prompt strategic attack option—and impose disproportionate costs on adversaries by forcing them to assign as many as four warheads to every US missile silo to ensure a “kill.”⁴⁰ SLBMs, meanwhile, are the most survivable. And bombers are the most flexible option—to say nothing of their added value in forcing adversaries to pour enormous resources into costly air defenses. Together, all three legs enhance each other’s survivability and complicate adversary planning. All three, then, should be reinforced to convince Beijing and Moscow that they cannot coerce Washington into submission at the strategic level of deterrence.

In terms of immediate next steps, the United States should prepare to upload warheads from the ready reserve stockpile on the existing 400 Minuteman III ICBMs and the 240 Trident D5 SLBMs carried on the Ohio-class fleet. US strategic force levels are, at this time, constrained by New START until February 4, 2026. But Russia has been in flagrant violation of the agreement since February 2023.⁴¹ Though the political costs of withdrawing from New START may be too high, the United States should ready itself to begin uploading warheads after the treaty expires. A max loadout of the land- and sea-based legs would increase Minuteman strike capacity from 400 to at least 980 deployed warheads and Trident strike capacity from 968 to 1,626. This upload option represents the most expeditious and cost-effective way to expand strike capacity in the near term. The Trident fleet, for example, could begin uploading within months.⁴² And the cost of uploading ICBMs and SLBMs would derive mostly from transporting and installing existing warheads from the reserve stockpile—a onetime cost of millions rather than billions of dollars.⁴³

The United States should also restore the 30 standoff B-52H bombers that were removed from the nuclear mission in 2015. Expanding the airborne leg’s strike capacity would lessen the operational strain on a dual-capable bomber force that, if deterrence fails, will be in high demand for conventional missions. It would also provide greater selectivity and flexibility at the theater level, as B-52H bombers—carrying ALCMs with non-ballistic trajectories—can operate from forward bases on the Eurasian periphery.

In the long run, the United States should swap out the existing Minuteman fleet for 400 Sentinel ICBMs (loaded with two or three warheads), examine the feasibility of a more survivable road-mobile Sentinel launcher, and expand the planned Columbia-class submarine fleet from 12 to 14. The United States will also need more from its B-21 stealth bomber program. The B-21 is set to replace the B-2 as America’s only dual-capable bomber capable of penetrating sophisticated integrated air defenses. Yet current planning calls for just 100 of these stealthy delivery vehicles. US planners should expand the program to at least 200 bombers to ensure that the airborne leg has enough slack to conduct conventional and nuclear missions across three theaters. To further alleviate the operational strain on the dual-capable bomber force, the United States should also expand the planned long-range standoff weapon program (currently set for 1,087 missiles) to have a long-range cruise missile for every mounting point in the B-52H and B-21 fleets.

Theater Nuclear Posture. In the near term, the United States should open discussions with its Asian and European allies about forward deploying nuclear forces in their respective theaters. Frontline states are increasingly anxious about the credibility of America’s extended deterrence guarantee. South Korea and Poland in particular deserve special consideration to be brought into a nuclear-sharing arrangement in which Washington maintains custody of forward-stationed nuclear weapons that in moments of crisis or conflict would be carried by South Korean and Polish dual-capable aircraft. To hedge against these allied consultations failing to produce tangible results, the United States should simultaneously explore the feasibility of redeploying an interim seaborne cruise missile that places a W-80 warhead into the Block V variant of the TLAM. This emergency measure would help offset Russia and China and provide a stopgap until the planned nuclear-armed sea-launched cruise missile (SLCM-N) enters service in the mid-to-late 2030s.

In the longer term, the United States should prepare to bring online SLCM-Ns on attack submarines. If the promise of this enduring, regional nuclear option fails to reassure South Korea and Japan, Washington may need to broach the idea of a NATO-like nuclear-sharing arrangement that suits Asia’s unique political dynamics. And, in Europe, if the forward-basing option falls through and the SLCM-N fails to assuage fears in Poland, Washington may need to consider the return of theater-range, road-mobile missile launchers. Above all, the United States requires more prompt, diverse, and survivable regional nuclear options. Dual-capable fighters stationed far from the Russian border are necessary but insufficient, given their vulnerability on the ground and in the air, the Kremlin’s demonstrated risk tolerance, and Poland’s growing fears. And neither bombers generated from the continental United States nor port visits of ballistic missile submarines have quelled allied concerns that Beijing has decoupled America’s strategic forces from their defense.

US planners’ failure to anticipate the emerging two-peer-plus threat environment has placed the American nuclear posture in a severe strategy-resource mismatch. Washington can no longer treat today’s deterrence landscape as if it is business as usual. To redress the widening gap between strike capability and target sets, US planners must tailor force requirements to both the distinctive coercive styles of its adversaries and the growing fears of far-flung allies.

Deterring and assuring across three theaters will ultimately depend on injecting greater strike capacity, selectivity, and flexibility into the US nuclear force structure. Implementing these adjustments will undoubtedly impose resource-intensive demands on the broader defense program. And given the synergy between conventional and nuclear deterrence, defense planners must ensure that reinforcing the latter does not come at the expense of the former, and vice versa. As the other chapters in this book demonstrate, however, America can afford to reinforce both its conventional and nuclear forces and thereby strengthen its overall deterrence. Thus, given the singular importance of nuclear weapons to the nation’s security, Washington should field a larger and more diverse nuclear posture that addresses today’s unprecedented threat environment.

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