7 December 2023

DELIBERATE NUCLEAR USE IN A WAR OVER TAIWAN: Scenarios and Considerations for the United States

Matthew Kroenig

INTRODUCTION 

The potential for a Chinese invasion of Taiwan may be the most critical flash point for a military conflict for the United States in the next five to ten years. Both the United States and China would be highly resolved not to lose such a conflict. For the United States, a defeat over Taiwan could call into question US security guarantees globally, which underpin the US-led, rules-based international order and the unprecedented period of peace and prosperity it has sustained since the end of World War II. For Beijing, restoring China to a position as a leading world power is key to the legitimacy of the governing Chinese Communist Party (CCP) and its general secretary, Xi Jinping. According to the work report delivered at the CCP’s Twentieth National Congress in October 2022, unification with Taiwan is required “for realizing the rejuvenation of the Chinese nation.”1 

A US-China war over Taiwan would be the first direct military conflagration between two nucleararmed superpowers, and the shadow of nuclear use would hang over the conflict. Given the high stakes, either side could possibly decide to use a nuclear weapon in such a conflict. While China espouses a declaratory policy of no first use of nuclear weapons, the US Department of Defense states bluntly that Chinese nuclear first use is possible.2 China, for instance, could decide to employ a few nuclear weapons against critical nodes in the US IndoPacific defense architecture as an early war-winning strategy. Alternatively, if China was losing, CCP leadership could order a nuclear strike to stave off defeat and compel a settlement. China is engaged in the most significant expansion of its nuclear force in the country’s history as a nuclear state, “allowing it potentially to adopt a broader range of strategies to achieve its objectives, to include nuclear coercion and limited nuclear first use,” according to the 2022 Nuclear Posture Review.3 

The United States also reserves the right to threaten the use of nuclear weapons to deter a strategic attack against itself or its allies and partners and, if deterrence fails, to employ strategic weapons to achieve presidential objectives.4 While the United States is investing in conventional capabilities to deter and, if necessary, defeat a Chinese invasion of Taiwan, a window could open in which China possesses capabilities for an invasion but the United States has not yet acquired the capabilities to deny the attack. In this instance, the United States might choose to use nuclear weapons against the Chinese invasion force to prevent the conquest of Taiwan. 

In the event of the use of a single or a handful of nuclear weapons in such a conflict, an extended nuclear exchange could occur. US strategists would need to carefully calibrate a US response to Chinese nuclear first use to make clear that Chinese leadership could not achieve its goals by further nuclear escalation, while minimizing the risk of unintended escalation. US nuclear first use could make threading that needle more difficult. While the goal of limited US nuclear use would be to convince China not to retaliate with nuclear weapons, an extended exchange—perhaps including strategic nuclear forces—could plausibly result. 

The United States should shape its Indo-Pacific force posture to reduce the risk of Chinese nuclear use, including by developing robust conventional forces and hardening and dispersing forces to make a nuclear strike minimally advantageous for China. US policy makers should also consider formally extending the US nuclear umbrella over Taiwan. The United States should consider whether existing forces are best suited to provide options to limit nuclear escalation in this conflict and, if not, which new forces would be helpful (e.g., theater-based, low-yield weapons capable of striking moving maritime targets). Because such a war could escalate, intentionally or otherwise, to an extended nuclear exchange, the United States should consider further investments in homeland missile defense, strategic offensive nuclear forces, and/or advanced conventional forces capable of nuclear counterforce operations. Finally, the United States should work with allies and partners such as Taiwan to prepare them for the risk of nuclear use against them and to train their militaries to better operate in a nuclear environment and mitigate civilian harm from nuclear effects. 

Other scholars have recognized the risk of a USChina war over Taiwan inadvertently escalating to nuclear use, but few have thought through each party’s rational incentives to deliberately employ nuclear weapons and how a nuclear exchange might play out. For instance, some scholars have considered how a high-intensity conventional USChina war could inadvertently generate nuclear escalatory pressures.5 But inadvertent escalation is not a necessary, or even the most likely, path to a US-China nuclear exchange in a Taiwan contingency.6 This paper is one of the few detailed treatments of deliberate nuclear use in a Taiwan Strait conflict as a part of a rational and deliberate strategy. This paper will lay out scenarios for deliberate Chinese or US nuclear use, evaluate the prospects for an extended nuclear exchange arising from such use, and consider recommendations for the United States to better prepare to deter and, if necessary, respond to nuclear use. 

STRATEGIC CONTEXT 

The US government has emphasized that China’s growing military power and malign behavior pose a significant national security challenge to the United States. The US Department of Defense has recognized China as its “pacing challenge.”7 The 2022 National Security Strategy proclaims that “[China] is the only competitor with both the intent to reshape the international order and, increasingly, the economic, diplomatic, military, and technological power to do it. Beijing has ambitions to create an enhanced sphere of influence in the Indo-Pacific and to become the world’s leading power.”8

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