Threats, assurances, and deterrence: Security Studies Program Director M Taylor Fravel contributes to an analysis of how to decrease the likelihood of conflict across the Taiwan Strait. Originally published here in Foreign Affairs.
As tension rises between Beijing and Washington over Taiwan, strategists on all sides seem to have forgotten what the American game theorist Thomas Schelling taught years ago: deterring an adversary from taking a proscribed action requires a combination of credible threats and credible assurances. Instead of heeding that lesson, a growing number of US analysts and officials have called for the United States to treat Taiwan as if it were an independent state and to abandon the long-standing policy of “strategic ambiguity” in favor of “strategic clarity,” defined as an unconditional commitment to use military force to defend the island in the event of a mainland Chinese attack. These calls have intensified since Russia’s invasion of Ukraine, with some commentators even advocating for formal recognition of Taiwan as a sovereign country. Still others have called for a permanent (and significant) deployment of US forces to Taiwan to lend credibility to the US threat of a military response to a mainland attack. In testimony before the US Senate last year, Ely Ratner, the assistant secretary of defense for Indo-Pacific security affairs, implied that the United States could never allow Beijing to control Taiwan because such an outcome would make it impossible to defend other US allies in Asia.
But shifting US policy toward support for Taiwan’s permanent separation from the mainland is more likely to provoke than to deter an attack on Taiwan. Deterrence requires credibility in both of its elements: threat and assurance. The threat requires signaling both the costs of a proscribed action and sufficient political will to impose those costs. The assurance requires conveying to the target, in a way that it can trust, that it will not be taken advantage of if it refrains from taking the proscribed action.
Avoiding war in the Taiwan Strait requires all sides to be deterred. At a minimum, Taiwan must be deterred from declaring formal independence, Washington must be deterred from recognizing Taiwan as an independent state or restoring a formal alliance with the island, and Beijing must be deterred from using military force against Taiwan to compel unification. All sides must not only be threatened with harm for crossing these redlines but also be assured that they will not suffer catastrophic losses to their interests if they refrain from these actions. Triangular deterrence has succeeded for over 40 years in keeping the peace across the Taiwan Strait. But rising tensions have made this delicate arrangement more fragile.
Since the beginning of the Trump administration, deterrence has begun to break down on all sides. Taiwan’s threat—its ability to exact a military cost from mainland China in case of an attack—has never been strong, and it is only now acquiring mobile weapons that might enable it to hold off an attack for a matter of weeks. Meanwhile, Taiwan’s assurance—that it will not eventually declare independence if it is not attacked—has weakened over time. Public opinion polls suggest that a growing number of Taiwan’s citizens see themselves as Taiwanese rather than as Chinese or some mix of both. Most citizens of Taiwan still support policies that maintain the status quo in cross-strait relations and oppose explicitly pro-independence policies that risk war. But the percentage of the population that supports eventual independence from mainland China is at an all-time high. Taiwan’s President Tsai Ing-wen has avoided taking actions that would provoke an attack. Her ruling Democratic Progressive Party no longer advocates formal independence for the island, instead asserting that Taiwan, officially known as the Republic of China, is already a sovereign and independent country and that any change in the status quo must be decided by all residents of Taiwan through a plebiscite. But Tsai has not assured Beijing that Taiwan will refrain from pursuing de jure independence. For its part, the opposition Kuomintang also maintains that the Republic of China has always been independent and sovereign. And it has shifted from a position of advocating eventual unification with mainland China, albeit only under certain conditions, to a position of seeking to lower tensions across the strait in order to preserve Taiwan’s de facto autonomy as long as possible.
Beijing’s balance of credible threat and credible assurance has also grown unstable. Mainland China has long been able to threaten to impose severe military and economic consequences on Taiwan if it were to declare independence. And now that Beijing has built up its military capabilities, it can also credibly threaten to impose such costs on the United States if it were to intervene in a conflict across the Taiwan Strait. But Beijing has failed to assure Taiwan that refraining from moving toward permanent separation or independence will be rewarded with restraint rather than answered by increased efforts to compel unification on mainland China’s terms. To the contrary, Beijing has greatly increased military pressure on Taiwan and warned that it will attack if it is unable to achieve unification peacefully. Beijing has not articulated a firm deadline by which unification must be achieved, but Chinese President Xi Jinping has stated that progress on unification with Taiwan is a prerequisite to fulfilling his dream of the “great rejuvenation of the Chinese nation,” for which he set 2049 as the target date.
On the US side, both aspects of deterrence have also weakened. In the past, the United States was able to credibly threaten an effective military response in the event of a mainland attack on Taiwan. Even if leaders in Beijing believed they would ultimately prevail, the cost of doing so appeared very high. In addition, Washington wielded the threat of painful economic sanctions. Meanwhile, through its consistent adherence across multiple presidential administrations to its “one China” policy—which, in the words of the 1972 Shanghai Communiqué, has meant that the United States “does not challenge” the position that Taiwan is a part of mainland China—Washington was able to credibly assure Beijing that if it did not use force against Taiwan, the United States would not support independence for the island and would not restore something akin to the 1954 mutual defense treaty between the United States and the Republic of China, which was terminated as part of the agreement between Beijing and Washington to normalize relations in 1979.
The credibility of both US threat and US assurance in the Taiwan Strait has been weakened. Mainland China’s military modernization, especially since the late 1990s, places at risk in new ways not only Taiwan but also forward-deployed US forces that might assist in Taiwan’s defense. For instance, mainland Chinese missiles, submarines, and cyber-capabilities now hold at risk US Navy ships, including aircraft carriers, as well as US aircraft, US space assets, and large US military bases in the Western Pacific such as those in Japan and Guam. These new vulnerabilities call into question whether the United States can mount an effective intervention in defense of the island. On the assurance side, the growing rhetoric in Washington to support Taiwan’s permanent separation from mainland China or restore something akin to an alliance relationship with the island increases fears in Beijing that waiting for a peaceful resolution of cross-strait differences will only result in the permanent loss of Taiwan.
SUBSTANCE OVER SYMBOLISM
To maintain peace and stability in the Taiwan Strait, the United States must restore both the credibility of its threat to impose costs on Beijing if it attacks Taiwan and the credibility of its assurance not to damage Beijing’s interests there if the mainland refrains from such an attack. To present a credible threat, the United States must reconfigure its military posture in East Asia. Instead of relying on vulnerable aircraft carriers and a few large, concentrated air and naval bases, Washington should adopt a more mobile, dispersed, and resilient posture that will be much harder for Beijing to attack and destroy. Often described as “active denial,” such a strategy would deny mainland China the prospect of a quick and cheap military victory over Taiwan.
The United States is already moving in this direction, including by adopting new army, navy, Marine Corps, and air force doctrines and by procuring large numbers of long-range antisurface and antiship missiles, many of which can outgun mainland Chinese systems. But the US military must also gain access to additional locations in the region from which to operate, harden its existing facilities to reduce their vulnerability to preemptive strikes, pre-position munitions and other supplies in the region, and make its military supply lines from the United States less vulnerable.
To that end, the United States should continue to emphasize to regional allies that they have a stake in peaceful, stable cross-strait relations and that they should therefore contribute to a moderate, responsible US strategy to deter mainland belligerence. At a minimum, the US military will need greater access to a more diverse set of locations in Japan to make its posture more resilient and harder to target, but it may also need such access in other countries, including the Philippines. To the extent possible, the United States should also try to enhance cooperation with allies to prepare for joint or coordinated military responses to a conflict over Taiwan. At the same time, Washington should continue to mount a global diplomatic effort to emphasize to Beijing the economic and diplomatic costs it would incur in the event of a conflict.
Taiwan also has an important role to play in deterring a mainland Chinese attack. It must demonstrate its ability to remain resilient during a blockade and impose high costs on an invading mainland force. Taiwan should create deeper reserves of strategic resources such as fuel and food in case Beijing elects to blockade the island instead of invading it. The United States should continue to press Taiwan to create more robust, mobile coastal defenses and air defenses, turning itself into a “porcupine” capable of inflicting real pain on an invading mainland Chinese military. Unlike Ukraine, which enjoys land borders with US allies, Taiwan would be extremely difficult for the United States to resupply in the event of a conflict. For that reason, Taiwan must stockpile and train in advance with the weapons it needs. It must also expand its civil defense capabilities, both to pose the threat of in-depth defense to an invading military and to distribute essential resources to the public during a blockade. The United States cannot help defend Taiwan if the island will not defend itself.
But credible threat is not enough to prevent a war. The United States must also restore credible assurance, making sure both Taipei and Beijing understand that its objective is not an independent Taiwan but rather peace and stability in the Taiwan Strait. Washington needs to make clear that it does not support independence for Taiwan, that it opposes any unilateral change to the status quo by either side, and that it will accept any outcome that is peacefully agreed to by mainland China and Taiwan. This has long been the official US position, but a series of statements and omissions by political leaders in Washington have cast the US approach into doubt, and at times US actions have contravened these statements. The Biden administration should therefore speak and act with greater discipline and consistency on Taiwan than it has so far. Senior officials should not refer to Taiwan as a country and should not say that Taiwan can decide unilaterally that it wants to be independent, as if the United States has no stake in such a decision. The United States should make clear that it is not pursuing sovereign status for Taiwan even as it presses for the island’s inclusion in international organizations that do not require members to be independent states, or for Taiwan’s meaningful participation short of membership in intergovernmental organizations such as the World Health Organization and International Civil Aviation Organization that require statehood for membership, or for the negotiation of bilateral trade and investment agreements that strengthen the US-Taiwan economic relationship. The Biden administration should continue to press Beijing to engage in direct discussions with Taipei’s democratically elected leadership and to seek a long-term resolution of cross-strait differences that meets the approval of the people of Taiwan.
The United States should also avoid symbolic political gestures that needlessly aggravate Beijing, focusing instead on substantive measures that make Taiwan and forward-deployed US forces in Asia stronger and more resilient. That means that US officials and politicians, including members of the US Congress and those campaigning for office, should refrain from making politically advantageous but strategically damaging statements about Taiwan. Recent calls for clarity in the US defense commitment to Taiwan do nothing to enhance the credibility of the US deterrent threat because Beijing already anticipates that Washington would intervene in a cross-strait conflict, although Beijing does not know how intensely or effectively Washington would do so. An unconditional US defense commitment, however, would likely undercut the essential deterrent component of assurance by appearing to restore a de facto alliance relationship between the United States and Taiwan, thus providing a blank check to future politicians on the island advocating for de jure independence. Similarly, calling for formal recognition of Taiwan as a sovereign state, as former US Secretary of State Mike Pompeo has done; or calling for the stationing of significant US forces on the island in peacetime, as former US National Security Adviser John Bolton has done; or designating Taiwan as a “major non-NATO ally,” as the original language of the Taiwan Policy Act of 2022 proposed, may all sound like ways to bolster deterrence of a cross-strait conflict. But if these policies were adopted, they would undercut the assurances to Beijing that are an essential element of deterrence, increasing rather than decreasing the likelihood of conflict across the Taiwan Strait.
THOMAS J. CHRISTENSEN is Director of the China and the World Program at Columbia University’s School of International and Public Affairs and a former U.S. Deputy Assistant Secretary of State for East Asian and Pacific Affairs.
M. TAYLOR FRAVEL is the Arthur and Ruth Sloan Professor of Political Science and Director of the Security Studies Program at the Massachusetts Institute of Technology.
BONNIE S. GLASER is Director of the Asia Program at the German Marshall Fund of the United States.
ANDREW J. NATHAN is Class of 1919 Professor of Political Science at Columbia University.
JESSICA CHEN WEISS is the Michael J. Zak Professor for China and Asia-Pacific Studies at Cornell University and a former Council on Foreign Relations Fellow on the U.S. Department of State Policy Planning Staff.
They are among the contributors to Avoiding War Over Taiwan, a report by the Task Force on U.S.-China Policy convened by the Asia Society’s Center on U.S.-China Relations and the 21st Century China Center at the University of California, San Diego, School of Global Policy and Strategy, from which this article is adapted.