China’s Legal Warfare Against Taiwan
In October 2025, Chinese police opened a criminal investigation into Puma Shen, a sitting Taiwanese legislator, on charges of “separatism”—the first application of Beijing’s 2024 judicial guidelines targeting “Taiwan independence diehards.” Within weeks, People’s Republic of China (PRC) state media broadcast calls for his arrest via Interpol. Chinese social media accounts circulated satellite imagery marking his home and office in Taipei. Two months later, the PLA conducted its largest blockade exercise around Taiwan in years, with state media listing “leadership decapitation” among the drill’s stated objectives.
A year earlier, these developments would have seemed like escalatory fantasies. But they follow a pattern. In 2024, a PRC court sentenced a Taiwanese activist to nine years in prison on a charge of “separatism.” It was the first time Beijing had jailed a Taiwanese citizen under this charge. Later, a Taiwanese publisher received three years for “inciting secession” for books he published in Taiwan. The legal infrastructure Beijing has been assembling for two decades is being activated, in sequence, against progressively higher-profile targets. If the U.S. policy community wants to understand where a Taiwan crisis is most likely to begin, it should spend less time studying amphibious ship counts and more time reading PRC statutes.
The “lawfare” campaign—Beijing’s use of legal instruments as tools of coercion—is the leading edge of China’s pressure campaign against Taiwan. It will almost certainly intensify before any military escalation. Indeed, Beijing may use legal fig leaves like “customs enforcement” to try to seize control of Taiwan’s semiconductor manufacturing base intact, without firing a shot. The United States and its allies have done virtually no coordinated planning for how to respond.
The PRC’s Lawfare Toolkit
China’s lawfare against Taiwan rests on two statutory pillars. First, the 2005 Anti-Secession Law specifies three deliberately vague conditions under which Beijing may resort to “non-peaceful” methods against Taiwan: (a) “If ‘Taiwan independence’ forces, under whatever name and method, achieve de facto Taiwanese separation from China”; (b) “If a ‘major incident’ occurs that would lead to Taiwan becoming separated from China”; and (c) “If all possibility of peaceful unification disappears.” The law leaves terms such as “de facto separation” and “major incident” undefined to preserve the flexibility to redefine red lines at any time. Second, the 2015 National Security Law broadens this umbrella, asserting PRC jurisdiction over any activities at all that Beijing deems threatening to its “core interests.” Together, according to the PRC, these laws assert supremacy over Taiwanese law and create the legal basis for Beijing to claim that anyone who acts in ways Beijing considers supportive of “Taiwan independence” is committing a crime under PRC law. The charge of “separatism” could theoretically be applied to any member of Taiwan’s governing Democratic Progressive Party, whose platform Beijing labels as separatist.
The coercion extends to claiming jurisdiction over Taiwan nationals anywhere in the world. Beijing has begun pressuring Taiwanese citizens visiting or working on the mainland to acquire PRC local identity cards—a direct challenge to Taiwanese sovereignty. Hundreds of Taiwanese citizens have been deported from third countries to China to face trial. Over 60 countries have extradition treaties with China that cover political offenses, and Taiwan’s government has warned its citizens about the risks of traveling to any of them. In June 2024, the PRC published formal guidelines for prosecuting “Taiwan independence diehards” under the separatism statutes, codifying the procedural framework for broader enforcement.
This domestic and extraterritorial legal campaign is reinforced by an offensive in international institutions. Central to this effort is Beijing’s campaign to redefine UN General Assembly Resolution 2758. The 1971 text recognized the PRC as “the only legitimate representative of China to the United Nations,” transferring the Chinese seat from Taipei to Beijing. Notably, the resolution’s language refrains from taking a position on Taiwan’s sovereign status. Beijing, in turn, has launched a major propaganda effort asserting, baselessly, that the UN has accepted the “One China Principle” and that Taiwan is therefore legally a part of the PRC under international law. As part of this campaign, sustained diplomatic pressure has led to Taiwan’s exclusion from the International Civil Aviation Organization, the World Health Assembly, and other international bodies.
These bodies don’t just coordinate flight routes and pandemic response—membership in them is one of the basic markers of standing in the international system. Each exclusion narrows the space in which Taiwan is recognized as a distinct actor, making it incrementally easier for Beijing to assert that the international community has already accepted its claims. If this revisionist reading prevails, Taiwan will have few remaining pathways to contest China’s actions through international institutions—and fewer governments willing to defend its right to do so.
The Escalation Pathway
It is precisely this erosion of Taiwan’s international standing that would lay the groundwork for more direct forms of coercion. The PRC’s lawfare campaign is not merely a complement to military pressure; it is the mechanism by which a quarantine or blockade could be legally justified—and, crucially, the mechanism by which Beijing could make a coercive move against Taiwan look, to much of the world, like a routine law enforcement action.
Consider the quarantine scenario that Robert Blackwill and Philip Zelikow first described in a 2021 Council on Foreign Relations report: Beijing’s customs authority announces that all goods and people entering and exiting Taiwan must first clear customs on the mainland. Existing PRC law already establishes a plausible basis for this claim. The rules could apply to all traffic, or only to specific categories—people convicted of a crime under PRC law, or shipments suspected of carrying “contraband” such as weapons. The latter allows Beijing to present itself to the world as exercising routine enforcement while simultaneously selectively strangling Taiwan’s ability to arm itself. Punishing only a few noncompliant Taiwanese operators would ensure widespread compliance, since private carriers have no interest in losing their ships or insurance coverage. Over time, Beijing could gradually escalate into this scenario without ever formally announcing new rules, outsourcing enforcement to Taiwanese and foreign operators themselves.
The more plausibly deniable Beijing’s pretext, the harder it would be for the United States to mobilize a coalition response. Beijing could claim it is cracking down on, for example, fentanyl precursors, or enforcing customs law that it insists has always applied to “Taiwan province.” Each pretext is absurd on its merits—but each is supported by statutes that Beijing has carefully put in place.
China has many options to escalate the lawfare campaign to just short of a full quarantine on Taiwan. It could demand that Taiwanese companies with business on the mainland share employee and customer data. It could curtail direct flights between Taiwan and third countries by pressuring airlines to route through the mainland. It could target Taiwanese officials by name through Interpol’s red notice system. This legal infrastructure is already in place, and can be activated in stages, each more coercive than the last, each plausibly deniable. The lawfare campaign is the connective tissue that links peacetime pressure to gray-zone crisis to outright conflict.
Why the Law Matters
There is a temptation in certain corners of Washington to dismiss the legal dimension of this problem. The Trump administration has a track record of little reverence for international institutions. The World Trade Organization’s (WTO’s) Appellate Body is paralyzed. Why should Americans care what Beijing does at the UN or in its domestic courts?
Because Beijing is pursuing its strategy through lawfare precisely because legal framing has political value. International law may not constrain great powers directly, but it shapes the calculations of every other state. Many smaller countries genuinely want the major powers to be bound by rules. But just as importantly, having international law on its side gives Beijing the fig leaf that third countries need to reason their way toward accommodation.
Consider the choice facing a developing country’s leaders in a quarantine scenario. Beijing is offering what looks like a painless resolution: Taiwan is under its customs control, but global trade continues, chips keep flowing, and no one needs to get hurt. Washington, by contrast, is offering the prospect of an economic crisis or even a shooting war. If Beijing can frame its quarantine as a legitimate exercise of sovereign authority—grounded in domestic statutes, supported by its reading of Resolution 2758, consistent with what it claims the UN has already accepted—that framing provides political cover for leaders who would rather not pick a fight with China. The legal argument isn’t aimed at convincing international lawyers. It’s aimed at giving foreign ministers a defensible talking point. If China could establish this principle, it could then pressure the companies exporting chips from Taiwan to the world to comply with PRC law.
In short: This is a pathway for Beijing to seize Taiwan’s semiconductor manufacturing base intact—without a fight.
This is why Taiwan’s status as a member of the WTO is so consequential. Taiwan participates in the WTO as the “Separate Customs Territory of Taiwan, Penghu, Kinmen, and Matsu”—a legal status that does not require statehood but does establish Taiwan as a distinct economic entity with rights under international trade law. A quarantine that seized control of Taiwan’s customs border would directly violate Taiwan’s WTO rights. It would, in essence, constitute one WTO member forcibly absorbing the customs territory of another. Taiwan could bring suits against China at the WTO in its own right.
The precedent matters far beyond Taiwan. If China successfully imposed a quarantine and the international community acquiesced, it might establish that a great power can use “law enforcement” pretexts to coerce any WTO member into surrendering control of its trade relations. Vietnam, the Philippines, South Korea, and Japan—all of which have territorial or maritime disputes with China—would draw the obvious conclusion. The WTO framework may be imperfect and weakened, but it remains the strongest multilateral legal basis for defending Taiwan’s economic autonomy. Failing to invoke it would be a strategic gift to Beijing.
Rules of Engagement for the Gray Zone
Before the legal questions surrounding a quarantine can be answered, the United States and its allies need to address a more immediate gap: The absence of coordinated rules of engagement for gray-zone coercion that falls short of a quarantine.
The Kinmen boarding incident of February 2024, in which China Coast Guard (CCG) officers boarded a Taiwanese tourist boat, and the Second Thomas Shoal confrontation, in which CCG officers violently boarded Philippine resupply boats, illustrate a consistent pattern: China uses “law enforcement” vessels rather than military ships, employs nonlethal but escalatory force, and calibrates each incident to test whether—and to what extent—the defender will respond. Taiwan, the Philippines, Japan, and the United States each have their own rules of engagement for these encounters. The problem is that these are not coordinated, and Beijing is adept at exploiting the gaps between them—creating situations in which an allied partner looks like the aggressor, or in which one country’s restraint undermines another’s credibility.
The United States and Taiwan should develop shared rules of engagement for Coast Guard and maritime encounters in the Taiwan Strait, with Japan and Australia brought into the process. Under what circumstances would Taiwanese vessels resist a forcible boarding? At what point would the United States or Japan provide escort? If a Taiwanese captain fires on a CCG boarding party and a Chinese sailor is killed, the political and legal consequences would cascade instantly. Both Taipei and Washington ought to know what the playbook is before that happens.
The Allied Coordination Gap
The broader problem is that the United States and its allies have done almost no coordinated planning for how to respond to a lawfare-driven crisis.
The Taiwan Relations Act (TRA) commits the United States to “maintain the 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 of Taiwan.” A quarantine would clearly constitute “other forms of coercion” under the TRA, and there would be an extremely strong argument that China had crossed U.S. red lines. But what exactly does “maintain the capacity to resist” require Washington to do in response to a quarantine that Beijing insists is a law enforcement action?
Under existing law, the president can order the U.S. Merchant Marine to resupply Taiwan, and Congress can authorize government-backed insurance for private carriers. These authorities exist. The question is whether anyone has planned to use them. The harder legal questions concern allied coordination. How would Japan justify participating in an escort operation? Under what legal framework would Australia or the United Kingdom contribute? The legal ambiguity in the U.S. One China Policy framework that once served American interests now serves Beijing’s, because it provides no clear trigger for responding to coercion that falls short of outright military attack.
Japan’s position is particularly important. In November 2025, Prime Minister Sanae Takaichi told the Diet that a Chinese naval blockade of Taiwan could constitute a “survival-threatening situation” (sonritsu kiki jitai) under Japan’s 2015 Legislation for Peace and Security—the legal threshold that would permit Japan to exercise collective self-defense. It was the first time a sitting Japanese prime minister had explicitly linked a Taiwan contingency to this legal framework, and Beijing reacted furiously. Takaichi’s statement moves the conversation from private reassurances to public legal positioning, though in the event of a crisis Japan’s cabinet would still have to weigh in to determine that a true emergency existed. But a single parliamentary statement does not constitute a coordinated allied plan. The U.S. and Japan urgently need to develop shared legal authorities and operational concepts for quarantine scenarios, building on Takaichi’s framework before the next crisis forces improvisation.
What Now?
The United States and its allies need a new toolkit to respond consistently and proportionately to China’s gray-zone coercion, deterring further escalation by signaling resolve and restraint. Here are five specific ideas.
First, the United States and its core allies need to develop a joint legal framework for responding to a quarantine. This should include pre-agreed positions on when China’s actions cross the threshold from “customs enforcement” to “coercion” under the TRA, under international law, and under each ally’s domestic legal authorities. The framework should be grounded in Taiwan’s WTO status. The core allies should prepare a joint declaration, ready to issue on day one of a crisis, labeling China’s actions as a “systemic national security threat” under Article XXI of the General Agreement on Tariffs and Trade charter. This would provide legal justification for subsequent allied trade actions and frame the response in terms that third countries can support, or at least tolerate.
Second, the United States, Taiwan, and regional allies need coordinated rules of engagement for gray-zone encounters now, before the next Kinmen or Second Thomas Shoal incident escalates out of control. This means shared protocols for maritime and air encounters with CCG and maritime militia vessels and a communication architecture that allows allied commanders to coordinate in real time.
Third, the allies need a coordinated strategy to contest Resolution 2758 revisionism. This means sustained diplomatic engagement with developing countries at the UN and public statements by senior allied officials affirming that the resolution did not settle Taiwan’s status. The argument should be made in terms that resonate politically: If Beijing succeeds in redefining 2758, it might establish the precedent that a great power can use legal instruments to strip another WTO member of its international personality. Every country with a border dispute with China should find that alarming.
Fourth, the allies should develop contingency plans for protective legal countermeasures. If Beijing begins charging Taiwanese officials with “separatism,” Washington and allied capitals should respond with targeted sanctions against PRC officials involved in the lawfare campaign. If Beijing pressures companies to comply with quarantine-related mandates, allied governments should provide legal safe harbors backed by government-provided insurance. Congress should pass legislation to automatically revoke China’s Permanent Normal Trade Relations status if China imposes a quarantine—a pre-commitment device that signals resolve.
Fifth, all of this planning needs to happen through a standing institutional mechanism. Ad hoc consultations during a crisis will not suffice. The United States should use existing channels—particularly with Japan, Australia, the U.K., and Canada—to establish a working group on Taiwan legal contingencies that meets regularly and develops options papers for senior decision-makers. This is the kind of allied coordination that the Allied Coordination Working Group, which I direct, is designed to support.
Beijing’s lawfare campaign is happening now, in plain sight, and it is accelerating. The question is whether the United States and its allies will develop a coordinated response before the crisis forces them to improvise one. History suggests that improvisation favors the side that has planned.
