1. Introduction

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For all their power, the United States and China are increasingly vulnerable. Each faces strategic dangers, from nuclear weapons to disruption of critical computer networks and space links.¹ Because their relationship is at once interdependent and potentially adversarial, the United States and China are especially vulnerable to each other: interdependence exposes each to effects of the other’s activities, malicious or not, while the potential for conflict impels each to acquire offensive capabilities against which defenses can be futile. Strategic vulnerability cannot be eliminated, only mitigated.

Of the two countries, the United States is stronger in offensive strategic capabilities, notably nuclear, antisatellite (ASAT), and cyber weapons. Yet it is also highly exposed to danger in these domains, confirming that power does not necessarily reduce vulnerability. If Americans thought before the 9/11 attacks that being the only superpower made them safer, they think otherwise now. Even its $600-billion-plus annual defense budget does not let the United States buy its way out of vulnerability.

Meanwhile, China’s striking economic and technological development is enabling it to acquire all forms of power, including offensive strategic capabilities. But China’s development is also making it more vulnerable, as it becomes more integrated at home and with the world and thus more susceptible to economic disruption. While the Chinese have long felt, based on their history, that weakness breeds vulnerability, they are learning that greater vulnerability can also accompany greater strength.

This book confronts the paradox that as power grows, so can vulnerability. The basic reason for this is that the same factors that produce modern power—technological advancement and economic integration—also increase exposure to risk. The book suggests a way to mitigate U.S. and Chinese strategic vulnerabilities to each another. It is written from an American perspective, with U.S. interests foremost in mind. But because the United States cannot escape its growing vulnerability to China unilaterally, Chinese agreement is needed. The book’s core idea is that mutual strategic vulnerability calls for mutual strategic restraint. Whether SinoAmerican distrust will preclude agreed restraint is one of the questions it tackles. But even with distrust, self-interest in avoiding harm—in a word, deterrence—can move both powers in this direction.

In becoming more vulnerable, the United States and China are not alone. With global economic integration and information networking, most nations are increasingly susceptible to disturbances and damage caused by other nations and transnational actors. The 300-year-old model of nation-states controlling their territory, vulnerable only to invasion, was shaken by the advent of strategic bombing and then nuclear weapons. On the chessboard where nations play, queens with stunning speed and unlimited range now endanger sovereign kings (and their realms). Against strategic offense, defense is getting more costly but not more effective, leaving fear of retaliation as the surest way to avert disaster. This has been the essence of nuclear deterrence, though neither the problem nor the remedy is confined any longer to the nuclear domain.

The increased vulnerability of sovereign states that began in the mid 20^th century with strategic bombing and nuclear weapons has been compounded by two factors that mark passage to the 21^st century: integration and information networking. The former has increased the exposure of states to each other’s products, services, data, money, ideas, surveillance, migrants, and travelers, including terrorists. Integration has also opened new domains in which nations interact: no longer just at sea, on land, and in the air but now also in space and cyberspace. While economic integration has brought growth to those nations that participate, it has also reduced their ability to escape risk.

Information networking has accelerated economic integration not only internationally but internally as well, as China’s transformation from a fragmented to a national economy shows. It is also demolishing the ability of sovereigns to control what their populations know. This heightens the potential for political upheaval, which is of more concern to Chinese than to American leaders.

Information networking increases vulnerability in another way: improved military targeting. It has yielded dramatic enhancements in sensors, data processing and sharing, geolocation precision and coverage, navigation, and guidance—thus, in the ability to deliver weapons at any distance with great speed and accuracy, and to defeat defenses. Information technology has made objects—fixed and moving, on land, at sea, and in the air—increasingly observable and vulnerable. Such advances are also evident in space and cyberspace, which are susceptible to targeting and also can serve as media for novel weapons, including electromagnetic and energy-based ones.

Although growing strategic risk affects weak and strong states alike, those that face the power/vulnerability paradox are the strong ones. Recall that the United States and the Soviet Union were simultaneously at their most powerful and their most vulnerable during the Cold War because the capacity of each to visit nuclear destruction made it the other’s primary target. Today, the conventional military superiority of the United States incentivizes adversaries, real and potential, to target its strategic vulnerabilities.² For all its power, the United States is hard pressed to protect its territory from nuclear attack, its satellites from ASAT attack, and its computer networks from cyber attack.

The United States and China are not mortal enemies, as the United States and the Soviet Union were. But their growing capacity to inflict strategic harm, when combined with the possibility of conflict, motivates each to be capable of striking at the other’s vulnerabilities, at least for deterrence. Fortunately, there are enough positive aspects of Sino-American relations that the two should be able to find ways to mitigate their mutual vulnerabilities. After all, even the United States and Soviet Union, despite their animosity, were able to manage their nuclear vulnerabilities through mutual deterrence. But while Soviet-American strategic peace was kept by reciprocal fear, there is reason to think—at least to hope—that China and the United States can manage their vulnerabilities with a quotient of reciprocal trust.

The distinction between mutual deterrence and mutual restraint is crucial. Although mutual restraint depends on mutual deterrence, it is less fragile and more likely to contribute to wider cooperation than fear-based deterrence alone. It implies that the parties are not fundamentally adversarial and that each seeks a relationship based on more than canceling out the other’s strategic threat. While mutual restraint does not depend on faith in good intentions, it can ease fears of hostile intent, thus reducing the danger of miscalculation and the collapse of restraint during crises. It also invites—indeed, requires—earnest dialogue and understanding regarding the shared problem of strategic vulnerability, as well as concrete steps to reinforce restraint.

There is no guarantee that both China and the United States would abide by agreements to exercise strategic restraint—that is, to refrain from escalation—in the event of conflict. This is why mutual deterrence is a prerequisite for mutual restraint. Even in the midst of war, the prospect of retaliation can prevent escalation if accords reached in peacetime cannot. Conditions for mutual deterrence exist in all three domains. At the same time, Sino-American agreement on the concept of mutual strategic restraint may help the two countries create a more cooperative relationship in general and thus reduce the likelihood of conflict.

Noting both the certainty of mutual fear and the aspiration of mutual trust, this book contends that the United States and China have both a need and an opportunity to adopt and apply the principle of strategic restraint as the best way to mitigate their vulnerabilities to one another. Present conditions in China, in the United States, and in Sino-American relations may or may not offer fertile ground for the book’s proposals for mutual strategic restraint. The time horizon of this study is about a decade, and it may take that long for awareness of strategic vulnerability to impel both nations toward an accord. Nevertheless, the ideas offered here can be grist for discussion within each nation and between them, looking toward the time when conditions will be ripe for their adoption.

The United States and China in an Age of Vulnerability

The United States and China will be the world’s most powerful states for at least the next decade, and probably longer. Though it is premature to proclaim the world bipolar, China has an impressive package of modern power: economic scale and productivity, technological prowess, spreading political influence, military capabilities, and human capital and creativity. Though their nuclear force is small compared to those of the United States and Russia, the Chinese believe that possessing more than an assured minimal deterrent is unnecessary and wasteful. Only the United States can match China’s ASAT and cyberwar potential.³

However, China’s expanding power will not prevent its vulnerability from expanding, any more than U.S. power has reduced U.S. vulnerability. Whether China’s leaders appreciate that its vulnerabilities are growing along with its power will determine whether they will have an incentive to accept mutual restraint with the United States. While the Chinese have long sought mutual restraint with respect to nuclear weapons, it is unclear whether they will accept and cyberspace. Given their strong advocacy of no first use of nuclear weapons, they clearly understand the concept.

Meanwhile, China’s growing offensive power in space and cyberspace is making the United States all the more determined to acquire offensive capabilities to disable Chinese satellites and computer networks, at least for deterrence. Because China will find it at least as hard as the United States does to defend its satellites and networks, its offensive power makes it a target for U.S. offensive capabilities. Conversely, because the Chinese will not tolerate U.S. monopolies in ASAT weapons and cyberwar, and because the United States will find it hard to protect its satellites and networks, it too will become more vulnerable.

How the United States and China manage their strategic vulnerabilities depends on their larger relationship, which combines convergent and divergent interests. The two share interests in an open, orderly, and expanding world economy; the stability of resource, product, and financial markets; international security as a condition for economic growth; effective multilateral institutions; and controlling violent extremism and other nonstate threats. They also have an immense stake in each other’s economic health, which encourages strategic restraint.

Yet U.S. and Chinese interests can also be at odds and occasionally collide. This is especially so in East Asia, a region vital to both nations, where China aspires to be the preeminent power but where the United States will not abandon its stabilizing presence and influential role. China is not content to let the United States obstruct its national unification or, regardless of Taiwan’s fate, its access to the Pacific. China may see the United States as a barrier to its regional ambition and potentially to the world’s seas, trade routes, resources, and markets. Although history teaches that established powers and rising ones do not inevitably clash (think of Great Britain and America), it also teaches that clashes are more likely when the rising power sees the established one as posing obstacles to its material interests (think of Germany and Great Britain or of imperial Japan and America).

One of this book’s load-bearing assumptions is that neither hegemonic struggle nor harmonious interdependence can fully explain present and future Sino-American relations.⁴The former ignores weighty shared interests that encourage accommodation; the latter relies on a romantic notion that sovereigns lose their urge for advantage when their economies become interdependent. Because reality lies in the middle, relations will be a mix of cooperation and competition, understanding and suspicion, partnership and rivalry. This duality in Sino-American relations is crucial for the idea of mutual restraint: a relationship that combines divergent and convergent interests supplies both the necessity and the opportunity for accord to limit the use of strategic power against one another. A relationship without conflict would not require such an arrangement, whereas one fraught with conflict would not permit it.

This book is not about Sino-American relations in general but about mutual restraint in using strategic power. By strategic power, we mean the ability to harm the other nation’s essential well-being for purposes of imposing one’s will by threat or attack. Essential well-being includes homeland security, population safety, state viability, and economic health (that is, productivity, employment, and availability of goods and services). With the deep involvement of both countries in the world economy, essential well-being extends to access to resources and markets, the ability to use both traditional and new lanes of trade and communications—oceans, space, and cyberspace. Of all the dangers to the well-being of the United States and China, offensive nuclear, space, and cyberspace capabilities have strategic significance because of the harm they could do.

Nuclear conflict can cause unspeakable destruction, knocking out satellites can cause widespread and lingering economic disruption, and degradation of critical information networks can cause major economic and societal shocks. Any of these sorts of attacks can be regarded as a deliberate blow to vital functions of the other nation, intended to weaken its resolve or ability to resist the attacker’s designs (yet another way to define strategic). A premise of this book is that both the United States and China will have enough offensive power in these domains to cause grave harm. Although the United States is and could remain superior to China in each of these three domains, there is no evidence that it can dissuade China from gaining greater offensive power in all of them.⁵ Quite the opposite is true: nuclear retaliatory forces, ASAT weapons, and cyber warfare are high priorities in China’s military modernization.

At a minimum, the Chinese believe they need offensive capabilities in these categories to deter and avoid being bullied by the United States.⁶This is clearly the case with respect to nuclear weapons. More ominously for the United States, the Chinese, or at least the People’s Liberation Army (PLA), may be motivated in space and cyberspace not as much by deterrence as by a belief that U.S. vulnerabilities can be exploited to China’s advantage in the event of conflict.

In sum, the advantages the United States has in offensive strategic capabilities do not reduce its vulnerability to China’s growing offensive strategic capabilities. Likewise, China’s efforts to reduce U.S. advantages will leave it no less exposed to U.S. offensive capabilities. Because neither China nor the United States will forego these forms of strategic power, and because divergent interests may cause frictions, crises, or conflicts, the security of each nation depends on the other’s restraint in the use of such power. Obviously, neither one would agree to restrain itself unilaterally. Moreover, because it is unrealistic if not risky to assume that understandings of reciprocal restraint can be negotiated in the heat of a crisis, it follows that some attempt should be made to fashion terms of restraint before crises occur. Given the nontrivial potential for Sino-American discord and confrontation, such an attempt should begin sooner rather than later.

Offense Rising

Defenses against nuclear, ASAT, and cyber weapons are difficult, costly, and yield diminishing returns versus offensive capabilities of large, advanced, and determined states like the United States and China. This offense dominance gives an edge to the side that invests comparatively more in offense. It gives both sides an incentive to invest in offense instead of defense, which in turn compounds the strategic vulnerability of both.

After 25 years of U.S. work on ballistic missile defense, it is as clear as ever that defenses can be overwhelmed with modest numbers of missiles and sophisticated attacks. The offense-dominant character of nuclear warfare also stems from the fact that a single weapon on a missile that penetrates a missile defense system can do horrendous damage (for example, destroy a city). If successful defense is defined as avoiding such damage, defense must stop all incoming missiles.⁷By the same standard, offense succeeds if any missile penetrates.⁸ With known technology, the odds of one missile penetrating improve sharply with increases in the size and complexity of attack.

Satellites—delicate objects moving predictably and conspicuously against the background of space—are much easier to destroy than to defend. Moreover, high-performance satellites cost much more than ASAT interceptors. Therefore, as the performance of interceptors improves and the cost of every additional one declines, it is far cheaper to multiply interceptors than to replace satellites. Once developed, interceptors can be readily increased in number.

Likewise, protecting information networks becomes increasingly difficult and costly as the scale and sophistication of the would-be attacker grow. After years of heavy investment in making networks more secure from intrusion, they are for the most part less secure. Hacking is far cheaper than network defense. After all, networks are meant to accommodate users’ needs for access, sharing, and collaboration. Strong forces of supply responding rapidly to demands for connectivity and convenience generally trump security. Short of undoing information-sharing, with huge negative economic consequences, defense must compete with the very purposes and virtues of networking.

Meanwhile, markets, firms, and supply chains for networks and their components have become global and integrated, with the United States and China top players in both production and demand. U.S. concerns about dependence on Chinese sources have grown as China graduates from making chips to making supercomputers, often based on technology of U.S. origin. Now that Chinese state-affiliated firms are competitive in network infrastructure—for example, data and cellular networks—U.S. concerns about insecure supply chains have merged with worries that made-in-China hardware and software within U.S. networks could be manipulated or disrupted for strategic purposes.⁹

Across all three strategic domains, as well as in conventional military capabilities, offense dominance and vulnerability are the result of advances in information sensing, processing, and sharing that facilitate targeting. Industrial-age military power swung between offense and defense dominance, depending on the physics of speed, distance, armor, weapons accuracy, and the like. In the digital age, however, offense dominance is persistent and even getting more pronounced, given the accuracy, timeliness, and distance of targeting.¹⁰ Using space and information technology, networked targeting capabilities are increasingly global, and they can deliver physical weapons and electronic agents alike. The United States is a world leader in the very technologies that underlie strategic offense dominance, and China is on its heels.

U.S. and Chinese military priorities reflect judgments on both sides that investments in offense are rewarding. The United States has declared that it will maintain the qualitative superiority of its strategic nuclear offensive forces (as long as nuclear weapons exist) and that its missile defense system is intended only for protection against small threats, such as Iran and North Korea.¹¹China concentrates investment in offensive strategic nuclear forces in order to have a credible deterrent. Neither the United States nor China can count on protecting its satellites; both are developing systems that can destroy or disable satellites. While neither country will divulge specific information about its cyberwar capabilities or operations, China is plainly active in network attack, and the United States is formidable in offense as well as defense.

Unless and until nonlinear scientific advancements make defense feasible against large nuclear, space, and cyberspace attacks, strategic vulnerabilities will persist and increase. Whether offense dominance will last is taken up later in this book. Because of the role and power of information technology and continuing integration of the world economy, it is almost sure to last for at least another decade.

Declining Costs of Strategic Attack

In addition to favoring offense over defense, technology is drastically reducing the costs of strategic attack. Until the mid-20^th century, any powerful state determined to bring about the collapse or capitulation of another state might decide to launch a massive land invasion, at great cost in lives and treasure to itself, not to mention to the victim. Napoleonic France and Nazi Germany tried, unsuccessfully, to conquer Russia; the North was compelled to invade the South to win the American Civil War, with huge casualties; Germany defeated France by invasion in the Franco-Prussian War and World War II, but lost World War I when its invasion stalled; neither Napoleon nor Hitler could subdue Great Britain because they could not invade it. The advent of strategic air forces gave strong states the option of bombing other states into submission, at substantially lower cost to the attacker. Although World War II and the Vietnam War revealed the limits of heavy bombing against states and peoples with the fortitude to endure, champions of strategic bombing can cite evidence that strong states can defeat weak ones from the air—Germany’s conquest of the Netherlands in World War II, the U.S. defeat of Iraq in the Gulf War, and the North Atlantic Treaty Organization’s defeat of Serbia.

Nuclear weapons provided those possessing them with a decisive way to impose strategic will on another state—at least a nonnuclear one—at very low cost to the attacker in either human or economic resources. However, the cost to the victim would be more apocalyptic than that incurred by invasion or heavy bombing. Even if not deterred by the threat of nuclear retaliation, states with nuclear weapons have shown great inhibition to use them as a substitute for the higher cost alternatives of invasion and conventional bombing. Only in the case of the U.S. nuclear attack on Japan was a state prepared to accept such high enemy casualties, given that invasion would have caused enormous American casualties.

With technologies available to destroy satellites and crash computer networks, states in possession of such capabilities can inflict immense harm, if not total defeat, on other states. Satellite and cyber attacks have the capacity to damage the essential well-being of those on the receiving end, at modest economic cost to the attacker—minor cost in the case of cyber attack—and with negligible immediate loss of life on either side.

The following three graphics depict the sharply declining costs of producing enough strategic damage to defeat another state. Figure 1–1 shows, in orders of magnitude, the economic and human costs of strategic attack as technology has evolved from land warfare to air warfare to nuclear warfare to antisatellite and cyber warfare. For purposes of illustration, it is assumed that all these strategic attack options have the same effect: to destroy the ability and/or sap the resolve of a state to resist an attacker. As technology has progressed from mechanized armies to long-range bombers to nuclear-armed missiles to information systems, the costs to the attacker have declined in both economic resources and lives.

Figure 1–2 shows that the same technological developments have reduced the expected casualties of not only the attacker but also of the attacked.¹² The most striking implication of this is that inhibitions about attacking due to expected loss of life on both sides may not apply with regard to satellite and cyber attacks. Anticipating no bloodshed and the resulting outrage, the threshold of justification for attack would be lower.

Table 1–1 summarizes how the five classes of strategic warfare compare in regard to the attacker’s expected casualties, the economic cost of delivering the attack, and the expected casualties of the state being attacked. In a nutshell, technological "progress" is making it cheaper and easier to harm another nation. This is another way of saying that even the most powerful states are becoming increasingly vulnerable to those who command those technologies. Conversely, powerful states, including China and the United States, could become less restrained about inflicting harm on one another as the costs to the attacker and expected deaths on both sides sharply decline— unless, of course, mutual deterrence and restraint take effect.

Table 1–1 suggests that technology has created options for practically "nonviolent" forms of strategic attack. Yet the potential economic damage done by denying the use of space or cyberspace is on the same order of magnitude as the economic damage from invasion or bombing. Because causing an economic shock and corresponding hardship could be strategically effective without causing death and destruction, those in possession of these new means of attack could be less hesitant to use them if they have important interests at stake.

The Case for Deterrence and Restraint

China and the United States are in the vanguard of these technological and economic trends. The dominance and declining cost of strategic offense and the resulting investment of both China and the United States in offensive capabilities compound their mutual vulnerability. Yet attempting to limit and reduce such capabilities through negotiated disarmament would not be fruitful. China will not negotiate away its hard-earned ability to maintain a credible retaliatory nuclear force, and antisatellite and computer network attack capabilities do not lend themselves to meaningful or verifiable limits and reduction. With both defense and traditional arms control being so unpromising, vulnerability will have to be mitigated by mutual deterrence—better yet, by agreed and institutionalized mutual strategic restraint.

Despite great differences in the circumstances, the way U.S.-Soviet nuclear peace was kept during the Cold War offers a starting point for how the United States and China can manage their growing mutual strategic vulnerabilities. A wider application of mutual deterrence to Sino-U.S. strategic relations is not without complications: although mutual nuclear deterrence is straightforward, deterring attacks on satellites and even more so on computer networks is different, conceptually and technically. How mutual deterrence and restraint apply across the domains will vary as much as the domains do.

Again, the stakes in Sino-American strategic relations are not ideological or existential, as those in the U.S.-Soviet relationship were. Therefore, the danger of actual strategic strikes by either against the other is less acute, at least in the nuclear domain. Moreover, while interdependence makes China and the United States more vulnerable, it also gives them both reasons not to harm the other’s well-being and thereby their own. For instance, China’s trade and financial interests would suffer badly from the loss of U.S. satellites or critical U.S. computer networks. Thus, deterrence by threat of retaliation could be reinforced by the risks of self-inflicted harm.¹³

Just as cooperative aspects of Sino-American relations could help mitigate strategic vulnerabilities, failure to mitigate those vulnerabilities could disturb those relations. The risks and fears of new forms of U.S. and Chinese strategic power and of unmitigated vulnerability could make it harder for the world’s two leading powers to work together. China could calculate that one or more forms of strategic offensive power could offset U.S. conventional military advantages and thus reduce its susceptibility to coercion, defeat, and humiliation. At the same time, the United States could come to rely increasingly on strategic escalation to ensure deterrence as China increases its military capabilities and its boldness in East Asia.

Thus, it cannot be assumed that mutual strategic restraint will happen spontaneously as conditions of mutual deterrence are met. It will come about only through Sino-American dialogue about vulnerabilities, capabilities, and intentions. It could take years before a dialogue bears fruit: even with shared awareness of the need for prudence, common assessments, concepts, and vocabularies will be needed before substantial accords can be reached. Meanwhile, new offensive capabilities are being developed, increasing vulnerabilities. So the process should begin now. Washington appears to have reached that conclusion. Whether Beijing has is unclear.

Issues and Analytic Approach

In sum, growing strategic vulnerabilities of the United States and China, given the dominance of offense over defense and the declining costs of attack, suggest that mutual strategic restraint is an important goal. But the path to that goal is paved with quandaries and risks. The chapters that follow will address these quandaries and risks, pointing to specific terms for mutual restraint in all three strategic domains as the book unfolds.

Because restraint in using strategic power must be reciprocal, the first hurdle is that the United States and China both must accept it. Divergent interests and competitive impulses in Sino-American relations are strong enough that whatever arrangements one side might judge to be advantageous, the other might suspect. If, for example, the Americans fear that China aims to dominate the western Pacific, and the Chinese fear that the United States aims to control their freedom of action in the region and their access beyond it, one or the other could be concerned that restraint at the strategic level might embolden the other to risk conflict below that level. The Americans may be hesitant to relieve Chinese fears of nuclear escalation, and the Chinese may be reluctant to relieve American fears of war in space or cyberspace.

As the established power with superior strategic offensive capabilities, the United States theoretically stands to lose more than China by excluding their use. U.S. strategic advantages give it the potential for socalled escalation dominance: the upper hand in a crisis or conflict by virtue of having less to lose from escalation than the adversary does. Weighed against this is the growing U.S. vulnerability, in absolute terms, to Chinese strategic offensive capabilities, and the prospect that escalation could cause great harm to the United States, irrespective of the harm it also causes China. This dilemma is addressed in chapter two, which examines U.S. views on China, Sino-American relations, the role of force, global security challenges, and long-term interests in East Asia.

China has a different calculus. It is presently at a disadvantage in strategic offensive power and also is increasingly vulnerable. Therefore, in theory, it stands to gain by mutual strategic restraint. Yet facing U.S. conventional military superiority, the Chinese may believe that they can exploit U.S. fears of strategic hostilities in space and cyberspace. Therefore, China might want to preserve its freedom of action and give the United States reason to fear escalation. On the other hand, with the United States preoccupied with threats elsewhere (such as terrorism), and with trends in the East Asian conventional military balance starting to favor China, mutual strategic restraint could prove advantageous for China, perhaps enabling it to dominate the region or at least to settle territorial disputes on its terms. Chapter three examines how the Chinese could weigh these factors in the context of Sino-U.S. and regional relations; it also examines how the views of China’s politicians and military could differ, while lacking the experience and mechanisms that the United States has to reconcile those views.

Chapters four, five, and six analyze how the concept of mutual strategic restraint might apply in the three domains. The answers depend in part on whether mutual deterrence, which assured Soviet-U.S. nuclear peace, can apply to space and cyberspace. On this, it is important to distinguish between nuclear deterrence, as practiced during the Cold War and since, and the deeper logic of deterrence that, although crystallized by the arrival of nuclear weapons, dealt with transcendent observations about human rationality in the face of danger.¹⁴ The core idea, that fear of retaliation may be the best way to avoid the use of strategic weapons when defense is futile, is not peculiar to the nuclear domain. Forms of deterrence not only apply but also are needed in space and cyberspace, given offense dominance and the declining costs of attack. Chapters four, five, and six develop these ideas in the three domains of Sino-American strategic relations.

Even if the United States cannot deny China the ability to deter a U.S. nuclear attack, it could be risky for the United States formally to accept mutual nuclear deterrence at a time when the conventional military balance in East Asia is starting to tilt in China’s favor. However, the United States has little chance of getting the Chinese to accept restraint in space and cyberspace if it will not do so in the nuclear domain.

The surest way of mitigating U.S. and Chinese vulnerability in space is through mutual restraint, founded on deterrence. Yet hostilities between Chinese and U.S. conventional forces cannot be ruled out; indeed, the potential for such conflict is one of the main reasons for concern about escalation to strategic domains. The fact that satellites play an increasingly critical role in military operations, especially for U.S. forces but increasingly for the PLA as well, raises a serious question: is Sino-American possible if one or both sides want to retain the option of disabling satellites that support combat against their forces? What complicates this is that many satellites that support military operations also perform important economic functions, leaving no sharp firebreak between the tactical and the strategic.

There are even higher hurdles to the pursuit of mutual restraint in cyberspace. Attacks on networks that enable opposing military forces to perform their missions can escalate rapidly and unpredictably into fullscale cyber war, with enormous damage to the U.S., Chinese, and world economies. Yet it is unrealistic to expect military forces not to attack networks used by the adversary to target and strike their forces. This might imply that Sino-American acceptance of restraint in cyber warfare would apply only when the countries are at peace; but this would fail to address the fact that the most likely scenario for general cyber war is via escalation from tactical-military cyber war.

While chapter four finds that neither country is interested in using nuclear weapons for warfighting, chapters five and six find that attacking satellites and computer networks may have warfighting utility. Yet the dangers in those domains of strategic escalation and harm to both nations are clear. This tension between military-operational necessity and nationalstrategic risk is an analytic conundrum and potential impediment to mutual strategic restraint. It may create tension between the needs of military commanders and the fears of national leaders in both China and the United States.

If warfighting utility is the greatest obstacle to mutual strategic restraint, the greatest risk may be that removing the danger of escalation to conflict in any or all of these strategic domains could weaken deterrence and make at least East Asia "safer" for the use or threat of conventional military force, particularly by China. Of special concern is the potential for conflict over Taiwan. Even if China is unlikely to use or threaten force in East Asia, Japan and South Korea might feel that the combination of declining U.S. conventional superiority and mutual strategic restraint could shift the region’s power-political balance toward China. This could disturb the equilibrium that the United States has sought for a century to preserve in this vital region. Chapter seven assesses the risks of conflict and instability resulting from strategic decoupling, how to mitigate such risks, and how to weigh them against the benefits of mutual strategic restraint.

Chapter seven also integrates the three strategic domains. China may see much to gain by locking the United States into mutual nuclear deterrence and no first use. But Chinese military commanders may believe that locking themselves into similar restraint in space and cyberspace is unwise. U.S. leaders may take the opposite view. Consequently, from a U.S. vantage point, it is advisable to link these domains as part of a general understanding on mutual strategic restraint.

Finally, chapters seven and eight suggest practical steps that the United States and China can take to converge on the goal of mutual strategic restraint, build confidence that each is committed to that goal, and avoid miscalculation. Chapter eight also examines what could happen if China and the United States do not adopt mutual strategic restraint, as well as whether such restraint would hold up if technology makes strategic defense more promising. It concludes by suggesting questions in need of further study.

It could take years before the world’s two strongest powers, each with its own experience and outlook, are both ready to seize the advantages, adopt the terms, and manage the risks associated with strategic restraint. This book is not meant to be the final word on this idea. Rather, it is intended to inform a journey that the United States and China must take together because of their common interests and despite their differences.

Notes

1. Other, "softer" dangers, such as environmental damage, disrupted energy supplies, and turmoil in financial markets, are also exacerbated by interdependence but lie outside the scope of this study.
2. Russia, for instance, is showing renewed interest in nuclear weapons and unabashed enthusiasm for cyber weapons as its inferiority to U.S. conventional military strength grows. In China’s case, the appeal of asymmetric capabilities could work against acceptance of restraint in space and cyberspace.
3. While capable of conducting sophisticated cyber attacks and of developing antisatellite (ASAT) weapons, Russia lacks the resources and technological depth to match China. This is not to say that principles of mutual restraint cannot prevail in Russian-American (or Sino-Russian) strategic relations—a possibility that is touched on but not developed in this study.
4. Another view of what is driving Sino-American relations can be found in Charles Glaser, "Will China’s Rise Lead to War?" Foreign Affairs 90, no. 2 (March–April 2011). It argues that even the "realist" view of Sino-American relations does not necessarily imply a likelihood of conflict because the current international system, more than that of the past, provides constraints on the use of power and mechanisms for resolving disputes peacefully. This view would seem consistent with the idea that China and the United States could agree on mutual strategic restraint.
5. The goal of dissuading China from attempting to compete strategically with the United States was pronounced early in the administration of George W. Bush. However, China’s increased allocation of resources for military capabilities in the ensuing years suggests that the Chinese were determined to become more, not less, prepared for the contingency of conflict with the United States.
6. As one of our Chinese interlocutors said, if the United States is seen as keen on certain capabilities, China will more likely than not emulate the United States, even if it is not sure how it would use the capabilities.
7. For a primer on understanding of the effects of nuclear war, including single weapons, we recommend Hans M. Kristensen, Robert S. Norris, and Matthew G. McKinzie, "Simulated U.S. and Chinese Nuclear Strikes," in Chinese Nuclear Forces and U.S. Nuclear War Planning (Washington, DC: Federation of American Scientists and Natural Resources Defense Council, November 2006), 173–196.
8. Missile defenses might still have some value in limiting damage in a nuclear conflict, but such dire circumstances would constitute a failure of both deterrence and policy.
9. Thanks to Martin Libicki of RAND for sharing this assessment.
10. Targeting depends on wide-area, high-resolution, and continuous sensing, on rapid data processing, on tracking, and on sharing target data among sensors and "shooters." The cost performance of these capabilities has improved and should continue to improve as microelectronics and digital networking do. Consequently, those being targeted must rely increasingly on interference, hiding, deception, and mobility, involving considerable cost, operational inconvenience, and mixed results. It is unlikely that targeting improvements will be reversed in the next decade with known technology. 2010).
11. Department of Defense, Nuclear Posture Review (Washington, DC: Department of Defense,
12. This discounts possible casualties resulting indirectly from the disruption of services—for example, health and public safety—caused by cyber or satellite attack.
13. In addition to the disruption of space-based and other networks of common interest to the United States and China, space debris from ASAT could be harmful to all spacefaring nations.
14. Thomas Schelling, in particular, applied game theory and other economic analysis to the particular (and pressing) problems of avoiding nuclear war and managing nuclear crises. But his reasoning could apply to any dreadful weapons in opposing hands against which defense is difficult, leaving fear of retaliation as the best way to avoid the harm from their use out of proportion with the matter in dispute. The right question is not whether space and cyberspace fit the nuclear deterrence case but how the general theory applies to those cases. In an excellent summary of lessons learned in a recent U.S. wargame involving deterrence in space and cyberspace, then–Maj Gen Susan Helms, USAF, writes: "Nuclear deterrence concepts that worked very well during the Cold War and still work extremely well today do not always translate in practice to the space and cyber domains. At the same time, the fundamental behavioral principles on which classical deterrence theory is based are still valid when applied to the nuclear as well as cyber and space domains." "Schriever Wargame 2010: Thoughts on Deterrence in the Non-Kinetic Domain," High Frontier 7, no. 1 (November 2010).