Whether deliberately pursued or not, these improvements will by necessity give Beijing more and better options for employing its nuclear weapons, especially in more limited and controlled ways. In the past, China’s nuclear forces were considered vulnerable and blunt instruments, messy weapons that would only likely be used at the very top of the “escalatory ladder”—for instance, against the cities of its opponents. Needless to say, this presumably rendered the bar for Chinese nuclear use exceptionally high, an inference fortified by China’s oft-trumpeted (if ambiguous and rarely fully trusted) “no first use” policy regarding its nuclear weapons.
But, armed with its new generation of nuclear forces, China will gain options for using them that are more discriminate in nature than those entailing massive strikes against American territory. Instead of only, practically speaking, having the option of striking at a major American or Japanese city, China will increasingly gain the ability to employ its nuclear forces in more tailored fashion—for example, against military facilities or forces, including in the region. This ability to use nuclear weapons in more limited and tailored ways will make China’s threats—explicit or implicit—to use nuclear forces more credible.
The consequence of this is that China’s nuclear force will cast a darker shadow over Sino-American competition in the Pacific. Thus, strategists and military planners in the United States and allied countries will need to take the possibility of Chinese nuclear employment in the event of conflict more seriously. This does not mean that China will reach for the nuclear saber early or often. But a more sophisticated force will give China better options for how it might seek to use these weapons not only, as in the past, as a desperate last resort, but also to deter U.S. escalation of a conflict—escalation the United States might need to resort to if it is to prevail.
THIS RAISES the third reason why nuclear weapons are likely to become more relevant in the Asia-Pacific. This stems from the unfortunate fact that the United States may lose the conventional military advantage it has historically enjoyed over China in maritime Asia. Such a loss would most plausibly be partial—China would be unlikely to seize whole the conventional upper hand in the region. But, having gained the advantage over some parts of the western Pacific, Beijing might, for example, attempt to force the United States into a situation in which Washington would be unwilling to take the necessarily escalatory steps to overcome or push back Chinese attacks. For instance, Beijing might gain conventional superiority around Taiwan and be able to block U.S. efforts designed to defend the island. In such a case, the United States might need to broaden the war, possibly by striking targets further into China and of greater value to the PRC’s leadership, in order to persuade Beijing to agree to acceptable terms. The plausible threat of a limited Chinese nuclear response would prove a substantial disincentive to pursuing such a course.
A loss of U.S. conventional advantages in maritime Asia could come about because of a U.S. lack of resolve or inattention, because of the scale and effectiveness of China’s substantial and ongoing military buildup, or because of some malign combination of both. Such a shift in the balance is more plausible in the foreseeable future regarding the western portions of the Pacific, but this apparent narrowing of the problem actually offers little comfort since the western Pacific is home to Japan, South Korea, Taiwan and the nations of Southeast Asia, and is the eastern gateway to the Indian Ocean and the Persian Gulf. Losing military primacy and thus regional strategic leadership there is hardly compensated for by preserving it over the Samoan Islands. Moreover, military primacy lost in the western Pacific is just as likely to be simply a stage on the way to further erosion as it is to be the terminus of a shift in the military balance.
In the event that the United States does lose its conventional advantage, Washington may well seek to rely on its own nuclear weapons to compensate for outright inferiority or for the inability of its conventional forces to fight back in a way sufficiently controlled to suit U.S. interests in limiting a conflict. This reliance would, in effect, be a return to U.S. policy during the Cold War, when Washington relied on its nuclear forces to offset Soviet conventional superiority in Europe. In particular, Washington would likely seek to exploit its superior ability to conduct a limited nuclear war to deter China from taking advantage of its conventional lead.
Nor would this be likely to be a unilateral move on the part of the United States. Rather, it is reasonable to expect that beneficiaries of U.S. security guarantees would press for Washington’s clearer and more emphatic adoption of such an approach. Even in a far more congenial security environment than the future sketched here, U.S. allies like Japan, South Korea and Australia have been insistent that the United States reaffirm that Washington’s security guarantee ultimately is rooted in its commitment to use nuclear weapons to defend them. If the Chinese are able to develop not only the A2/AD capabilities but also the strike and power-projection assets needed to overcome U.S. conventional superiority, it seems reasonable to expect that U.S. allies will urge Washington to substitute for that conventional deficit with the nuclear force they already see as vital to their security.
THIS COURSE will seem unappealing to many, not least in the United States, given the risks it will entail for Americans. But this disquiet points to the fourth and final reason why nuclear weapons are likely to become more salient in the Asia-Pacific: the prospect of further nuclear proliferation in the region. If, as China grows stronger and more assertive, its conventional military power begins to outweigh that of the United States in maritime Asia, and that shift is not met by a greater U.S. reliance on its nuclear forces or some other effective countervailing steps, then those countries of Asia traditionally allied to Washington—countries that cannot hope to match China’s strength at the conventional level—may ultimately see getting their own nuclear weapons as essential to deterring China’s exploitation of its growing strength.
It is worth emphasizing that this will particularly be the case if these nations view a weaker United States as lacking the resolve or the ability to use its nuclear weapons on behalf of its allies, since in such a case they will be exposed to Chinese coercion. This is no fantasy; polls in South Korea already show substantial support for an indigenous nuclear-weapons program, and South Korea, Japan, Australia and Taiwan have seriously contemplated pursuing their own nuclear arsenals in the past and might do so again. In other words, in such a scenario a cruel dynamic will take hold in which diminishing U.S. conventional advantages will lead to pressure for greater emphasis on nuclear forces, but, in light of China’s own advancing nuclear capabilities, such reliance itself will be decidedly less attractive.
The loss of U.S. conventional advantages would leave Washington with a series of unpalatable options. Relying more on nuclear weapons might raise the costs and risks of conventional war with China and thus fortify deterrence, but those costs and risks would increasingly redound not only against the PRC but also against the United States and its allies. Ignoring or refusing to confront the nuclear implications of China’s growing conventional advantages, on the other hand, would increase the impetus toward proliferation among Washington’s allies and partners.
Such developments would put enormous pressure on what has been, since the end of the Cold War, a relatively easy dual pursuit of credible extended nuclear deterrence and nonproliferation. In the unipolar era, one policy served the other, and neither was very risky or costly. But during the darker days of the Cold War, there were bitter debates about whether the risks that extended deterrence involved for the United States were worth the benefits of nonproliferation. After the collapse of the Soviet Union, those debates effectively vanished. But as China grows stronger, it will be harder and riskier for the United States to credibly extend nuclear deterrence against Beijing to U.S. allies—perhaps much harder—which will mean that using it to forestall proliferation will also be harder and riskier. The greater the danger posed by China’s military and the broader its ambitions, the less plausible it is that Washington will be able to—or will want to—serve both masters. Thus, the more threatening and ambitious Beijing appears, the less likely it is that the nuclear order of the Asia-Pacific will endure.
NONE OF these four trends pushing toward the greater salience of nuclear weapons in the Asia-Pacific should—or will—be welcomed in Washington or in allied capitals. But hoping they will not materialize will not be sufficient to stave them off. Rather, the most effective step Washington—and, importantly, its Asian allies—can take is to strive relentlessly to maintain the U.S. and allied military edge in maritime Asia. As Clausewitz pithily put it, “The best strategy is always to be very strong.” But keeping this margin will require profound changes in how the United States invests its defense resources and in how it commits them. It means shifting away from the model of a “balanced force” designed to cover all bases and toward one concentrated first and foremost on prevailing in the most consequential forms of military conflict. And it means committing those forces less to elective interventions serving peripheral interests while husbanding them for use in deterring and, if necessary, defeating our most formidable potential adversaries, of which the most daunting is China.