Military Aspects of Deterrence and Reassurance Regarding Cross-Taiwan Strait Conflict

This Policy Brief analyzes the military aspects of the situation in the Taiwan Strait, where Mainland China’s relative power has been increasing. The author discusses the risk of war and how it can be avoided through a mix of deterrence and reassurance among the three parties: Mainland China, Taiwan, and the US. The author concludes by suggesting systematic dialogue on many levels to avoid accidents and above all to reduce the risk of a nuclear exchange.

 

Contents

• Abstract
• Introduction
• The quest to avoid while preparing for war
• The need for deterrence as well as reassurance
• Military capabilities
• Credible deterrence and reassurance
• Is time on Mainland China’s side?
• Avoiding accidents
• Avoiding the use of nuclear weapons
• Reassurance through dialogue

Abstract

This Policy Brief[1] analyzes the military aspects of the situation in the Taiwan Strait, where Mainland China’s relative power has been increasing. The author discusses the risk of war and how it can be avoided through a mix of deterrence and reassurance among the three parties: Mainland China, Taiwan, and the US. The author concludes by suggesting systematic dialogue on many levels to avoid accidents and above all to reduce the risk of a nuclear exchange.

Introduction

The consequences of large-scale military action between People’s Republic of China (PRC) and Taiwan would be immediate, severe, and long-lasting throughout East Asia and globally. The United States might engage on behalf of Taiwan, risking general war between nations with the world’s two largest economies and most lethal armed forces.The last time the world’s states with the largest GDPs fought an extended war was in the Second World War, over eight decades ago. Since then, military arsenals have become much deadlier and now include nuclear weapons, the United States possessing the second most warheads (behind Russia), and China the third (though far fewer than the U.S.). In an intense protracted conflict, military and civilian casualty figures among the belligerents and those providing support, and others simply caught in the crossfire would likely exceed numbers seen since 1945. Additionally, kinetic and cyberattacks against the opposing side’s terrestrial, maritime, and space-based communications, informational, transportation, and energy infrastructures would have crippling economic effects. The collateral disruption of regional and global trade, investment, and finances would be massive, dwarfing the impacts of the two “Oil Shocks” of the 1970s, the Great Financial Crisis of 2008, or the Coronavirus Pandemic of 2020.

The quest to avoid while preparing for war

Given the enormous potential costs and uncertainty of outcomes, leaders in Beijing, Taipei, and Washington do not desire a clash of arms.Yet all consider worst case scenarios and understandably direct their militaries to prepare for a wide range of contingencies, including the possibility of a full-scale invasion of Taiwan by the Chinese People’s Liberation Army (PLA).

President Xi Jinping has emphasized that the Mainland seeks peaceful reunification with Taiwan, but has also asserted, “No matter how the situation on the Taiwan island evolves and no matter how external forces try to interfere, the historical trend that China will and must achieve reunification is unstoppable.”[2] Neither he nor any of his predecessors have ever renounced the use of force to achieve reunification. Thus, a credible military tool provides the Mainland with the ultimate coercive leverage.

The Armed Forces of Taiwan are called upon to maintain a force that can deter PRC military action through its capabilities and readiness and, should deterrence fail, be prepared to mount an effective defense. In spite of the challenges, discussed below, it still fields a professional, high-tech military comprised of 188,000 active- duty troops and 1.7 million reserves; moreover its defense budget has been increasing since 2017.

The United States military posture is informed by the 1979 Taiwan Relations Act (TRA) enacted by the US Congress immediately following the termination of official relations with the Republic of China (Taiwan); it includes multiple security-related provisions. Importantly, beyond making available defense articles and services necessary to enable Taiwan to maintain a sufficient self-defense capability, it also requires the United States to maintain the military capacity “to resist any resort to force or other forms of coercion that would jeopardize the security, or the social or economic system, of the people on Taiwan."[3] US Presidents since that time, in their capacity as Commander-in-Chief, have directed the U.S. Indo-Pacific Command (until 2018, U.S. Pacific Command) to plan accordingly.

So, while China, Taiwan, and the United States do wish to avoid a military clash, the armed forces of all three are instructed by their civilian leaders to be prepared for a wide range of combat contingencies. Military force is but one of many pillars of comprehensive national power. As the military theorist Carl von Clausewitz wrote in his classic, On War,[4] “War is nothing but the continuation of policy with other means.” In other words, the decision to employ military force (or, in case of an accident, to escalate or deescalate), is a political, not military decision. Hence it is difficult to disassociate military deterrence and reassurance from politics and diplomatic strategies in general, and especially in the complex case of China, Taiwan, and the United States.

The need for deterrence as well as reassurance

Nevertheless, this paper attempts to focus on the military aspects of deterrence and reassurance across the Taiwan Strait and offer modest suggestions to reduce tensions and enhance mutual understanding between China, Taiwan, and the US.

First of all, the concepts of deterrence and reassurance are interrelated and it is useful for the purpose of clarity to provide definitions. Deterrence is the practice of discouraging a nation-state from taking unwanted actions, such as an armed attack. Its logic relies on convincing a potential aggressor that the cost of attacking outweigh the perceived benefit. This is achieved by making the adversary believe that the target, possibly with the assistance of others, is capable of inflicting unacceptable damage in retaliation or defeating the attack outright. Such a strategy aims to prevent an attack by creating the credible threat of a strong effective response.

Reassurance, on the other hand, refers to actions designed to build trust and confidence between states, often in the face of potential conflict or uncertainty. It is a way of mitigating risk and promoting cooperation. In the security domain, an assurance might be a stated commitment of one state to come to another’s assistance if the latter faces aggression from a third party, or a pledge by a state to an adversary to condition its response to a conflict between the latter and a third party based upon the causal circumstances. Deterrence may work best if it is combined with credible reassurance. The adversary should be convinced that if it allows itself to be deterred, it will not be subject to adverse action and its decision not exploited as a sign of weakness.

The concepts are distinct but have commonalities.

A state can hope to deter a rival from taking offensive action against a partner, but at the same time attempt to assure the rival that it will discourage its partner from taking what the rival state might deem provocative actions. The Cold War strategies of the United States and Soviet Union, especially beginning in the mid-1960s, were informed by the concepts of deterrence and reassurance, to include in their respective relationships with important allied or partner nations.

However, fundamental to the viability of both concepts is the capability to respond as communicated and the perceived will to do so when tested. So, if a state does not believe an adversary seeking to deter it from taking a certain action has the capacity to do so, deterrence becomes problematic. Or if a party is offered assurance from another that it will come to its defense if attacked, but the former doubts the reliability of the latter, the assurance may not be reassuring and thus may not achieve the desired effect.

Hence, when examining China, Taiwan, and US military deterrence and reassurance in Taiwan Strait scenarios, one must consider capabilities and will across the three dyads.

Military capabilities

Regarding capabilities, when planning for any potential high-intensity protracted conflict between the PLA and Taiwan Armed Forces (TAF), both sides consider the cross-Strait miliary balance and the capabilities of US forces that might intervene. Especially since the mid-1990s, the PLA-TAF balance has swung significantly in the direction of the former. For example, the PRC now exceeds Taiwan by a factor of 14 on annual defense spending, 9.4 for active-duty military personnel, 64 for the number of people reaching the age for military service annually, 4.25 for fighter aircraft (though Taiwan’s inventory is more rapidly aging on a comparative basis), 23 in GDP (important for logistics and sustainability), and 265 in size of territory (important for operational depth and dispersion). Of course, the PLA could not bring to bear all of its combat power against Taiwan because it is responsible for the nation’s defense across 22,500 kilometres of borders, whereas almost the entire TAF would be committed to a cross-strait conflict.

Still, the difference in the PRC’s and Taiwan’s military capabilities is huge and continuing to grow. The difficulty of planning and executing high-intensity operations that the PLA might be called upon to perform, most notably a full-scale invasion of Taiwan that would rival the 1944 Allied Normandy operation and the 1945 US invasion of Okinawa in scope, complexity, and intensity, would obviously give pause to the Chinese High Command. Add to this that such operations would be performed by untested commanders and troops (unlike the Allied forces at Normandy and Okinawa, which included many veterans whose experiences ranged from two to four years of intense combat, and a number of these having previously participated in major amphibious operations). However, in recent years the frequency, scale, duration, and sophistication of PLA exercises rehearsing blockade and invasion contingencies have grown significantly. It is uncontestable that without early and robust US intervention, the PLA will be able to defeat the TAF across the full spectrum of military operations if its political leaders are willing to absorb the costs and risks.

Of course, after the 1995–1996 Taiwan Strait Crisis, when the PLA was directed to truly focus on cross-strait scenarios and began receiving the resources needed to modernize the force, it has always considered the most important planning factor, beyond the readiness of the TAF and will of the Taiwan people, US military capabilities. In March 1996, the US arguably deterred the PRC from escalating its coercive military exercises against Taiwan by dispatching two of its aircraft carrier battle groups to the areas around the Island. Today, some three decades later, US simulations of a much larger scale intervention in a cross-strait conflict all result with American forces taking punishing losses and often in their abject defeat. The United States military is developing new doctrine and weapons systems to address its eroding military superiority, but the tyranny of distance, limited forward basing options, and looming fiscal constraints due to budget deficits make for immense challenges. It faces two additional problems in the event of a protracted war: 1) America’s armed forces have global responsibilities and it would be unable to concentrate all of its combat power in the Western Pacific region; and 2) its defense industrial base is not fit for the purpose of supporting an extended high intensity war as it would struggle mightily to replace the anticipated heavy loss of combat systems and to produce sufficient munitions and critical spare parts.

Thus, while US conventional capabilities that could be brought to bear in Taiwan Strait contingencies have increased over the past 30 years, they have significantly decreased in the metric that most matters here—its capabilities relative to PLA capabilities that can also be brought to bear. While the US military can inflict huge costs on the PLA in direct combat, it will likewise suffer significant losses. This leads to consideration of intention or will. A state may still elect to use military force even at great risk if a vital interest is at stake and there are no viable alternatives to defend that interest.

Credible deterrence and reassurance

When considering credibility, the starting point is the rather unique nature of US deterrence in this instance. Since the United States established diplomatic relations with the PRC and the Taiwan Relations Act was enacted, Washington has followed a policy of deliberate ambiguity regarding its hypothetical response to a conflict across the Taiwan Strait. The policy involves not explicitly committing to defend Taiwan in the event of an attack by China, while also not explicitly disavowing the possibility of intervention.The former is designed to deter Taiwan from unilaterally declaring its de jure independence which would be inconsistent with the US position advocating peaceful resolution of the cross-strait question, whereas the latter seeks to deter Beijing from using force to unilaterally change the status quo. However, if the military advantage, as noted above, is shifting to China and potential costs of intervention dramatically increase for the United States, what are the PRC’s and Taiwan’s assumptions about the credibility of American intervention?

In Taiwan, public polling allows one to gauge the people’s confidence in US intervention. A National Chengchi University's Election Study Center survey conducted in March 2025 indicates that 42.7% thought it certain or likely the US would not intervene militarily, up from 31.7% the year prior. And during that same period of time those disagreeing with the proposition that the US was trustworthy reached 59.6% up from 50.0% in 2024.
Some of this declining confidence in US credibility may be due to recognition of the change in the US–China military balance, though this possibility cannot be measured.Regardless, the American people’s foreign policy preferences have traditionally been shaped by the US Government and national political leaders. It is too early in President Trump’s second term to conclude that America is definitely adopting a more isolationist, Western Hemisphere-oriented strategy, and that a popular consensus of support may be slowly emerging. However, there are growing indications that this is the case.If so, this will further undermine efforts of the US to deter PRC military coercion against Taiwan since credibility will be doubted. The will of Taiwan’s leaders and their people to strengthen their own defense capabilities may also be impacted knowing the increasing difficulty of deterring China in the absence of a timely and determined US intervention. There can be no credible deterrence without sufficient capability and the perceived will to employ it, two conditions which for the first time since 1979 can no longer be assumed in the context of a US response to cross-strait clash of arms.

We now turn to reassurance, which was earlier defined as efforts to build trust and confidence between states as a way of mitigating risk and promoting cooperation and as a way to increase the likelihood that deterrence will work. Forms of military reassurance across the three dyads of China, Taiwan, and the US can be conceptualized, but are difficult to effect in practice since they are contingent on overarching political relations and diplomatic strategies, are complicated —as is deterrence—by the peculiarities of America’s strategic ambiguity policy, and often cannot be disentangled from deterrence itself. On the final point, if for example, Beijing was to somehow consider reducing the current operational tempo of its military activities around Taiwan to help build trust and confidence with Washington and Taipei, PLA “hawks” might oppose such a course of action arguing that since the credibility of Taiwan and US deterrence is steadily declining, why reassure?

Given the conceptual and policy challenges discussed above, but in keeping with the theme of the Toda Peace Institute workshop “Scope for Reassurance on the Taiwan Issue”, we must ask if there are any realistic proposals that might enhance military reassurance across and around the Taiwan Strait, and reduce tensions and improve mutual understanding between the armed forces of China, Taiwan, and the US?

Is time on Mainland China’s side?

One might argue that if it is confident US and Taiwan relative military capability will continue to decline relative to those of China in cross-strait scenarios, and US resolve to intervene is weakening, the Chinese Communist Party (CCP) leadership can adopt a more relaxed approach. On the other hand, if the CCP leaders should believe that China has already reached the top of its relative power, they could decide that there is a limited window of opportunity to reunify.America at some point in the coming 5–10 years might enjoy a rejuvenation, China might suffer a serious economic downturn coupled with unfavorable demographics, or there might emerge new technologies and systems favorable to the defense. These are all wild cards that must be considered.

Taiwan, if persuaded that the US was disengaging from the Western Pacific militarily, might become willing to compromise and begin substantive talks with the PRC more on the CCP’s terms, or it could strive to increase its own defensive capabilities and seek other security partners, though this would be a difficult task since in at least this instance, the US seems the indispensable nation.

As noted above, it is not clear at this juncture how the United States will define its future security interests in East Asia and the Western Pacific. If President Trump’s Russia and Europe policies are indicative, we would assume Washington will retreat. Yet, it is too early to tell. Trump’s bombing of Iran in June 2025 indicates that he is willing to accept great risk.

Common to all of these scenarios are three mutually shared military interests: 1) a desire to avoid accidents between military forces if there is no underlying plan(s) of the two sides involved to initiate combat operations; 2) to ensure the existence of off-ramps should a crisis begin to spiral out of control; and 3) to avoid the use of nuclear weapons by the United States and China. These are addressed in turn.

Avoiding accidents

Accident avoidance has long been a topic of discussion between the US and Chinese militaries and several modest protocols have been established between the two sides including the Military Maritime Consultative Agreement or MMCA (1998) and Rules of Behavior for Safety of Air and Maritime Encounters MOU (2014 with an annex added in 2015). China’s long-standing position has been that accidents could best be prevented if US forces did not operate in close proximity to its coast and in its expansively claimed seas and Exclusive Economic Zones, whereas the US asserts that its forces will globally “fly, sail, and operate wherever international law allows.”[5] Thus, Beijing tends to view agreement to talk about accident avoidance without addressing accident prevention as de facto acceptance of the US position. The two sides should continue to pursue dialogue on accident avoidance. Given current bilateral tensions and with ultranationalists on both sides likely to demand escalatory responses should two warships or military aircraft unexpectedly collide, the need for such dialogue has never been greater. It might be possible and helpful to consider establishing parallel but linked talks which address PRC concerns about accident prevention.

One key to quickly finding offramps in a crisis is for the two sides to have multiple trusted means of communication that are frequently validated. This entails repeated institutionalized interactions between leaders and empowered staffs which can create a modicum of trust, even if substantive agreements cannot be reached. Protocols such as the MMCA with provisions for emergency meetings to manage crises should be reinforced. Crisis management procedures should be a prioritized agenda item between Beijing and Washington, which increasingly manage their bilateral policies with a top-down command style, a recipe fordisaster in a complex crisis demanding clarity of information and the synchronization of numerous bureaucratic actors. A good first step might be an agreement on crisis management principles such as: multiplicity of channels, clarity, timeliness, maintenance (i.e, regular testing), standardization (i.e., developing common vocabulary and SOP’s), and openness. Meaningful talks will only begin, however, if explicitly supported by the two Presidents, either in Track 1 or 1.5 formats.

Avoiding the use of nuclear weapons

Avoiding crossing the nuclear threshold during a rapidly escalating war across the Taiwan Strait would be of paramount concern not only to Washington, Beijing, and Taipei, but to the entire world. The Russia–Ukraine War, the recent deadly skirmishes between India and Pakistan, and uncertainties on the Korean Peninsula and the Middle East indicate that it is foolhardy to assume that a severe Taiwan Strait crisis is immune from the possibility of a nuclear exchange through misperception, accident, or even an act of desperation. That assumption is hubris of the first order. Given the existential consequences, even a 1% probability of the use of nuclear weapons merits serious efforts at risk reduction. Strategic stability talks have long been a priority of the United States, but China with an existing nuclear arsenal less than one-tenth the size of America’s, is understandably not eager to come to the table (though it is engaged in an unprecedentedly rapid expansion of its interconnectional missile force that will triple in size to 1000 warheads by 2030). This paper is not the place to elaborate on arms control talks and confidence building measures, which under the best of conditions must eventually involve third parties beginning with Russia, are technically fraught with cyber and the surety of communications now topics that must be included, and are likely to be protracted requiring on the US side sustained bipartisan domestic support. The point is that, in spite of the many impediments, the two sides must agree on the importance and urgency of strategic stability talks and take action.

Reassurance through dialogue

Last, although perhaps most problematic, the goal of establishing a PLA–TAF dialogue focusing on accident avoidance and crisis management should never be abandoned. The conditions for such to occur do not and perhaps never have existed. Taiwan’s political leaders are likely reluctant to permit TAF leaders to engage with their PLA counterparts, understandably nervous about losing control of the narrative and policy itself. And PRC leaders probably want to exact political concessions from Taipei and Washington before "gifting" the TAF a seat at the table with the PLA.Still, should China become more relaxed if it perceives declining US commitment, it might change its calculus; in such a situation, Taiwan may find it useful to consider dialogue as part of a broader hedging strategy.

Notes

[1]This Policy Brief builds on a paper presented at the Toda Peace Institute Research Cluster on Taiwan, which met in Tokyo on June 13–14, 2025. For a report on another Research Cluster on China–US relations, see Kai He, “US–China Reassurance: Theory and Practice,” Toda Summary Report No. 217, 31 March 31, 2025: https://toda.org/assets/files/resources/policy -briefs/tr-217_us-china-reassurance_he.pdf For two Policy Briefs emerging from the Cluster on China-US relations, see Carla Freeman, “Toward A ‘Reassurance Spiral’ in US–China Relations,” Toda Peace Institute Policy Brief No. 124, 9 June, 2025: https://toda.org/policy -briefs-and- resources/policy -briefs/toward-a-reassurance-spiral-in-us-china-relations.html and Zhou Bo, “Trust but Talk: How to Manage China–US Competition,” Toda Peace Institute Policy Brief No. 226, 2 July 2025: https://toda.org/assets/files/resources/policy -briefs/t-pb-226_trust-but-talk_zhou.pdf

[2]“Xi says trend of China's reunification is unstoppable”, Xinhua, May 7,2025: https://english.news.cn/20250507/97acee7092f446db81da43e2d8192fdb/c.html

[3]https://www.ait.org.tw/policy-history/taiwan-relations-act/

[4]Clausewitz, C. (2007) Carl von Clausewitz: On War. Oxford: Oxford University Press.

[5]https://www.reuters.com/article/world/carter-says-us-will-sail-fly-and-operate-wherever-international-law-allows-idUSKCN0S72MG/

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