The Nuclear Shadow: How Atomic Weapons Shape Taiwan Strait Deterrence Without Being Used
No nuclear weapons have been used in combat since 1945. Their influence on the Taiwan Strait is nonetheless pervasive and structural. The nuclear arsenals of the United States and China — and, less directly, those of Russia, Britain, and France — shape every aspect of the conventional military competition in the strait, the escalation calculus that each party brings to crisis management, and the limits that major power decision-makers apply to their own coercive behavior. Understanding Taiwan Strait risk without understanding the nuclear dimension is understanding a building without understanding its foundations.
The American extended deterrence commitment to allies in the western Pacific covers Japan and South Korea explicitly under the US nuclear umbrella. Taiwan is not a treaty ally and is not explicitly covered. The ambiguity of the American commitment to Taiwan’s defense — the strategic ambiguity that has characterized American policy since 1979 — extends to the nuclear dimension: would the United States use nuclear weapons or threaten their use in defense of Taiwan? This question has no public answer and probably has no definitive private answer, because the answer depends on scenario variables that no administration has been willing to specify in advance.
China’s nuclear arsenal has been expanding significantly. From a relatively small, land-based, minimum deterrence posture — a few hundred warheads in silos and on road-mobile launchers — the PLA Rocket Force has been growing toward a larger and more diverse force that includes submarine-launched ballistic missiles, a growing ICBM inventory, and the development of hypersonic glide vehicles. American intelligence assessments have consistently raised their projections of the eventual size of China’s nuclear force. The expansion is driven partly by Chinese assessments of the minimum force needed to maintain credible deterrence against American counterforce capabilities, and partly by a strategic decision that a larger force provides more coercive leverage in regional crises.
The escalation pathway in a Taiwan conflict is what makes nuclear weapons directly relevant to a conventional military competition. If the United States intervenes militarily in a PLA operation against Taiwan, it is engaging in direct combat with the military forces of a nuclear-armed state. That state’s leadership must calculate, in real time and under the pressure of battlefield losses, whether the situation calls for nuclear signaling, nuclear demonstration, or nuclear use. The thresholds that nuclear strategists have spent decades analyzing in the abstract become operational decisions made by specific individuals under conditions of fear, uncertainty, and incomplete information. The theoretical models are not comforting in this application.
The Chinese concept of nuclear escalation management has evolved in ways that are opaque to outside analysts but that produce some clear signals. China has maintained a no-first-use policy on nuclear weapons — a commitment that it will not use nuclear weapons against non-nuclear states and will not use them first against nuclear states. The commitment has been questioned by American analysts who note that it is a declaratory policy rather than a technical constraint, and that the same missile delivery systems can carry conventional or nuclear warheads, blurring the distinction between a conventional missile strike and a nuclear one in the confusion of a rapidly developing crisis. The concern about inadvertent nuclear escalation — a conventional strike misidentified as nuclear, or a nuclear-capable missile misidentified as carrying a conventional warhead — is real and has been discussed in both American and Chinese strategic literature.
Taiwan itself abandoned a nuclear weapons program in the 1970s and again in the 1980s under American pressure. The political decision to rely on American conventional deterrence rather than develop an indigenous deterrent has been validated by the durability of the American commitment over subsequent decades. It could be revisited under conditions where the American commitment appeared less reliable, though the diplomatic, economic, and security costs of a Taiwanese nuclear program would be severe.
The nuclear dimension of the Taiwan Strait is not visible in daily operations, not reflected in the daily ADIZ incursion count, not priced in the insurance premiums on cross-strait shipping. It is always there. The conventional military competition in the strait occurs within the boundary condition that escalation to nuclear use is possible. Neither side wants to cross that boundary. Neither side can guarantee it will not be crossed if the conventional conflict goes badly enough for the losing party.