How many nuclear weapons is enough? The question has haunted policymakers and scholars for 80 years. Early in the Cold War, the United States expanded its nuclear arsenal rapidly in response to the Soviet threat. But beginning in the 1980s, as the two nuclear powers sought ways to reduce nuclear risks, arms treaties helped cut the size of those arsenals significantly, and stockpiles decreased by 80 percent. Now, circumstances are pushing the United States to consider the size of its nuclear arsenal once again. Over the past six years, China has nearly tripled the number of nuclear weapons it has, and according to the U.S. Defense Department, the country is on track to have over 1,000 by 2030. China is not yet a nuclear peer to Russia and the United States, which each deploy roughly 1,550 nuclear weapons in keeping with the limit set by the 2010 New Strategic Arms Reduction Treaty, but parity may be Beijing’s goal. Meanwhile, the last formal barrier to a U.S.-Russian arms race fell away when New START expired earlier this year.
Faced with these rising dangers, the Trump administration announced in March that it would conduct what it called a “nuclear strategy review.” Some strategists recommend that the review include a call for a larger and more diverse nuclear arsenal. A larger arsenal, proponents of expansion argue, would provide the United States with a wider array of choices, especially for an in-kind response to low-yield theater nuclear attacks. Although Russia and the United States have nearly the same number of weapons, Russia possesses a greater number of theater nuclear weapons, which, unlike strategic nuclear forces, are designed for tactical use on the battlefield. China may also be developing more of these types of weapons. Advocates of expansion propose that if Washington can match any nuclear attack blow for blow, Beijing and Moscow will be less likely to initiate a nuclear exchange. According to Trump administration officials, the nuclear review will look at this “theater nuclear forces issue” to “identify where there may need to be changes or additions made.”
The United States should take additions to its nuclear forces off the table. The country already has a vast and diverse enough supply of nuclear weapons to unleash devastation on an adversary in the case of a nuclear attack. The purpose of nuclear deterrence is not to have an answer for every weapon in an adversary’s arsenal, but to avoid crossing the nuclear threshold in the first place. Moreover, introducing new theater weapons could provoke an arms race for which the United States is ill equipped and invite risks of inadvertent escalation that would only make the country more vulnerable. Rather than focus on expanding and diversifying the U.S. nuclear arsenal, Washington’s deterrence strategy should attend to the modernization of its existing strategic forces, which is behind schedule, and of its conventional arms, which are not fit to deter the United States’ greatest military threats, especially Chinese military aggression in the Western Pacific.
MAXED OUT
When the foundations of U.S. nuclear doctrine were laid early in the Cold War, escalation was understood as a ladder. When states encountered crises, their retaliatory actions would follow a vertical climb to more dangerous “rungs.” But escalation is unlikely to follow such a neat path, as Undersecretary of Defense for Policy Elbridge Colby argued in May; instead, as he said, there are ways that nuclear powers can shape “the limits of a conflict” and influence how their opponents respond. The goal for modern U.S. nuclear doctrine, therefore, should not be an abstract conception of superiority at all levels of the escalation ladder but practical options to constrain and deter the adversary. The proposal to introduce new theater nuclear forces in Asia or Europe follows the outdated logic that escalation will progress in a rational, orderly way with increasing levels of violence and harm. It does not follow modern reality.
Without arms controls in place, Washington does need to modernize its strategic nuclear forces—high-yield weapons whose purpose is to hold valuable targets at risk—to deter and defend against a nuclear attack on the American homeland or on U.S. allies’ territory. It has been trying to do so for years, since the U.S. Senate ratified New START in 2010, but with mixed results. As part of a deal to gain Senate support for the treaty, U.S. President Barack Obama approved a multidecade program to upgrade the existing nuclear arsenal and delivery systems that is now costing at least $1 trillion. The decision paved the way for defense contractors and national laboratories to begin replacing bombers, ground-based intercontinental ballistic missiles, submarines, warheads, and military communications systems.
More than 15 years later, most of the United States’ nuclear modernization efforts are over budget and behind schedule, despite significant investments in workforce, infrastructure, and congressional appropriations that fulfill and sometimes exceed the funding the Pentagon has requested. In 2015, for example, Congress required that 80 plutonium components for nuclear weapons be built by 2030; Department of Energy officials have since deemed the task impossible. The Sentinel intercontinental ballistic missile program was at least 81 percent over budget in 2024, and its first flight test has been delayed by about four years. The B-21 bomber program, which is on track, is the exception, not the rule. The United States is now at risk of nuclear disarmament by default. When the current systems reach end of life, replacements may not be ready. New work orders to build new weapons would only further stretch the nuclear enterprise’s capacity.
CROSSING THE RUBICON
Expanding the U.S. arsenal would not only distract from modernization efforts. It would also invite new risks. A U.S. buildup would likely trigger a steady arms race with other nuclear states—the very outcome that Democratic and Republican administrations worked for decades to avoid through negotiations and mutual arms reduction agreements with Russia. And given the slow pace of the current nuclear modernization drive and the heavy burdens already falling on the U.S. defense industrial base, the United States today is not well positioned to win such a race.
The danger would not stop there. The greater the number and diversity of nuclear weapons, the greater the number of possible miscalculations and signaling problems in a crisis. For example, it would be difficult to distinguish between a nuclear-armed cruise missile that is launched from a fighter jet or submarine and a conventional missile. If the United States builds these capabilities, the Chinese and Russian militaries could mistakenly believe that an incoming conventional U.S. munition is nuclear. And because of the uncertainty, the risk of nuclear use would rise exponentially.
As long as no U.S. leader wants to fight a nuclear war, additional nuclear options, including more low-yield weapons, will be extraneous. Nuclear weapons are not effective for coercing an adversary during a conflict. If Washington responded to a nuclear attack with a nuclear weapon, whether that weapon was of similar yield or caused comparable damage, its opponent would not likely back down. Damage assessments would be hazy. Leaders would be likely to take on more, not less, risk, becoming more inclined to widen the war and respond with more nuclear attacks, including on U.S. territory. Deterrence requires that an adversary perceive both that a U.S. leader will use force and that an alternative course of action is preferable. A more diverse U.S. nuclear arsenal complicates any attempts to reassure the adversary that there is a better way out of a crisis. Ultimately, the potential benefits of expanding the U.S. nuclear arsenal do not justify the costs.
This is not to discount the rising nuclear threats from China and Russia. In 2018, Russian President Vladimir Putin announced that Russia would test dangerous new nuclear delivery systems that can loiter near the U.S. coast or maneuver at hypersonic speeds. China has built new silos in its western desert and has tested ballistic missiles in the Pacific. Neither U.S. nuclear weapons nor U.S. missile defense systems such as Golden Dome are likely to eliminate novel Russian systems or China’s nuclear expansion. Still, the United States’ 1,550 deployed bombs and warheads deter nuclear attacks from both China and Russia, provide counterstrike options to limit damage to the homeland if nuclear war does occur, and fulfill U.S. security commitments to allies and partners. Once China has nearly as many nuclear weapons as Russia and the United States, Washington may have new opportunities to pursue new arms control agreements with Beijing and Moscow.
THE NONNUCLEAR OPTION
The United States has long had good reason to place limits on its nuclear forces. In 1964, Defense Secretary Robert McNamara made the point that nuclear bombs would have diminishing returns once 400 strategic warheads—far fewer than Washington had at the time or has today—struck Soviet cities. Arms control agreements between Moscow and Washington since the 1970s have allowed the United States to avoid costly arms races. Dedicating funds to defense research and development enabled the U.S. military to achieve comparative advantages in conventional warfare capabilities, including advanced reconnaissance, combined arms, and precision strikes. Innovative conventional weapons still deliver options for U.S. presidents.
The Trump administration should similarly be thinking about nuclear weapons in the context of the United States’ broader military and deterrence strategy. Nuclear posture reviews have consistently affirmed, over the last four decades, that weapons in the U.S. arsenal are defensive, meant to deter aggression, and defeat peer adversaries if deterrence fails. In practice, the primary means of demonstrating the United States’ resolve to deny and defeat its rivals is conventional. The U.S. bombing of Iranian nuclear facilities in 2025 and Ukrainian drone strikes on military and industrial facilities deep within Russia over the last two years were conventional operations that achieved their tactical objectives. It would be sensible practice to include nuclear reviews as part of the national defense strategy process, as the last U.S. administration did. Isolating nuclear strategy from conventional force decisions is a mistake.
To be sure, conventional forces are not a substitute for nuclear weapons. But to credibly deter China and Russia, the United States needs nonnuclear options. The Trump administration has weakened U.S. conventional deterrence over the past year by pausing arms sales to Taiwan, shifting munitions to the Middle East, and beginning to withdraw American troops from Germany. Those steps must be reversed, and Washington must increase production of conventional forces capable of facing persistent threats in Asia and Europe, which includes both exquisite, or expensive and technologically advanced forces, as well as cheaper, mass-produced forces. U.S. policymakers should follow through on the promise of the third offset, an approach set out in 2014 for using unmanned and autonomous systems to counter Chinese and Russian military advances. With advanced conventional forces produced at scale, the United States can make the costs of war too high for China or Russia to initiate a conflict.
It is true that the global nuclear environment is changing. The United States must meet the prospect of two nuclear peers with foresight and planning. But the solution is not simply amassing more weapons. Building a larger and more diverse nuclear arsenal would put Washington on a path to undermining, rather than strengthening, deterrence. To counter both China and Russia, the United States must focus on modernizing its existing strategic nuclear capabilities and strengthening its conventional deterrence to preclude escalation. Because once a conflict transcends the nuclear threshold, no one can win.
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