February 22, 2023

Avoiding the Brink

Escalation Management in a War to Defend Taiwan

By: Stacie Pettyjohn and Hannah Dennis

Executive Summary

The United States is entering an unprecedented multipolar nuclear era that is far more complex and challenging than that of the Cold War. This report examines potential triggers, thresholds, and targets for Chinese nuclear use as well as options for the United States and its allies and partners to avoid and manage escalation. It uses the results of two exploratory tabletop exercises (TTXs) focused on how China’s expanding nuclear arsenal could impact the risk of nuclear escalation in a conventional conflict over Taiwan.

From these two TTXs, the authors derived tentative insights into how nuclear escalation in a war over Taiwan might unfold and identified areas where further research is needed. First, the expansions and improvements projected for China’s nuclear forces will provide it with a wider range of coercive options. With a secure second-strike capability and more diverse theater nuclear options, China may be willing to brandish its nuclear weapons to attempt to deter the United States from entering a war. There are few incentives to conduct nuclear strikes early in such a conflict, but a war over Taiwan might well lead to a protracted war between the great powers—another area where more study will be critical. The authors also found that American policymakers today might not find the PRC’s nuclear threats credible because of its smaller arsenal size and historic policy of no first use (NFU). Furthermore, the authors found that attempts to degrade key conventional capabilities might lead either side to cross the other’s red lines, setting off an escalatory spiral and transforming a regional conflict into a great-power war. Both the United States and China will have to weigh the value of eliminating certain targets with the risk of crossing an adversary red line. Last, the authors found an asymmetry between the targets available to the United States and China in a Taiwan contingency. With fewer categories of targets to strike and types of capabilities with which to strike them, the United States may have fewer options to manage escalation. All these findings merit further study.

The two TTXs, conducted in summer 2022, pitted a U.S. Blue team against a Chinese Red team in a war over Taiwan. The two wargames were designed as a controlled comparison to focus on the impact of one specific variable—the size and composition of the PLA’s nuclear arsenal—on the Red team’s decision-making and its propensity to deliberately escalate and on the Blue team’s ability to defend its allies and partners while managing escalation. By holding most other factors constant but changing Red’s nuclear force structure, the authors aimed to concentrate on the role that nuclear weapons played. In TTX 1, the players had a notional 2027 order of battle with a nuclear arsenal of about 700 warheads, diverse in yield and delivery system type and range. The second TTX, set in 2030, included a similarly diverse Red arsenal of over 1,000 nuclear warheads. After analyzing the results of both exercises, the authors contextualized and expanded the findings through research on existing literature on nuclear deterrence and escalation.

Key Findings and Recommendations

FINDING

A more survivable and diverse nuclear arsenal provided Red with coercive options. A larger, more diverse nuclear arsenal not only increased the survivability of China’s second-strike capability but also gave the Red teams the ability to threaten or employ nuclear weapons in a limited fashion. Neither Red team felt the need to employ a nuclear weapon early in the conflict, but both issued nuclear threats at the start of the war to dissuade U.S. involvement. In one TTX, Red employed a low-yield nuclear weapon against Guam in response to Blue team attacks on its mainland.

RECOMMENDATION

Continue to explore how China might use nuclear weapons in a war over Taiwan and in other scenarios. Given the uncertainty about China’s nuclear policy and doctrine, it is important to consider how China could use the weapons it is developing.

FINDING

Red saw little advantage in the employment of nuclear weapons early in a Taiwan conflict. Because China’s conventional capabilities are expanding with its nuclear capabilities, the Red teams did not feel pressured to use nuclear weapons early in a conflict, although they were willing to brandish them.

RECOMMENDATION

Examine escalation dynamics and war termination during a protracted conflict. A growing body of evidence suggests that a short, sharp war in which China achieves a fait accompli or the United States defeats the initial invasion is unlikely.

FINDING

Neither team believed that its opponent would follow through on its nuclear threats. Many Blue players seemed to place undue faith in U.S. escalation dominance because of its larger nuclear arsenal and secure second-strike capability. Blue players had trouble believing that Red would cross the nuclear threshold, given its current and past doctrine and posture, and underappreciated the fact that Red did not need nuclear parity to consider limited nuclear use. The Red teams were willing to consider limited nuclear use because they did not believe that Blue would respond with a nuclear weapon in kind and thus they could keep the conflict from unduly escalating.

RECOMMENDATION

Begin a campaign to educate national security officials about the implications of China’s growing nuclear capabilities. American thinking about nuclear weapons and deterrence is shaped by the legacy of the bipolar Cold War era and outdated thinking about China’s nuclear capabilities and policy, which could lead to misunderstandings and miscalculation.

FINDING

Attempts to degrade key conventional capabilities could trigger escalation. To win the conventional fight, both the United States and China have an incentive to strike the other’s territory, but such attacks cross Blue or Red red lines and thus came with significant risk of setting off a tit-for-tat escalation spiral.

RECOMMENDATION

Better integrate nuclear and conventional planning to deliberately manage escalation. Since the end of the Cold War, nuclear weapons and deterrence have been siloed off from conventional military plans and operations, which should change with the implementation of integrated deterrence.

FINDING

Asymmetric target sets favor China and provide it with more options to manipulate risk. The United States’ force posture is distributed across the sea, allied territory, noncontiguous U.S. territories, noncontiguous states, and the continental United States; outside of the invasion force, most of China’s most important military targets are located on the Chinese mainland. This fundamental asymmetry provides China with more graduated options than the United States to strike important military targets while avoiding the U.S. homeland.

RECOMMENDATION

Consider whether the United States needs more conventional weapons or graduated nuclear options that can be employed against Chinese forces to provide it with more options for manipulating risk. It is not clear that different weapons will offset the fundamental distinction between the target sets, but the United States needs to develop creative concepts or additional conventional or nuclear weapons to be able to manipulate risk and manage escalation.

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Authors

  • Stacie Pettyjohn

    Senior Fellow and Director, Defense Program

    Stacie Pettyjohn is a senior fellow and director of the Defense Program at the Center for a New American Security (CNAS). Her areas of expertise include defense strategy, post...

  • Hannah Dennis

    Former Research Associate, Defense Program

    Hannah Dennis is a former Research Associate for the Defense Program at CNAS where she also supports the CNAS Gaming Lab. Her research focuses on the future of warfare, defens...

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