As US President Donald Trump’s second term unfolds, Taiwan finds itself manoeuvring with a familiar but less predictable security partner. The United States remains, by capability and necessity, Taiwan’s primary security guarantor, offering arms sales, training and the credible prospect of intervention should China resort to unification by force. Yet under Trump’s leadership, credibility—the willingness, not just ability, to act—is becoming increasingly uncertain.
The distinction between reliability and credibility matters profoundly. Reliability refers to the material capacity and consistency of an ally’s support, its ability to deliver on its commitments through hard power. Credibility, by contrast, concerns political will: the perceived likelihood that those capabilities will be used when tested. In deterrence theory, credibility acts as the multiplier of hard power, converting potential strength into believable resolve. Without it, even the strongest partner casts a weaker shadow.
Trump’s recent remarks have only amplified doubts about US resolve over Taiwan’s security. Responding to a question on the likelihood of a conflict over Taiwan, Trump said: ‘I think we’ll be just fine with China. China doesn’t want to do that.’ By downplaying the increasing risk of a crisis in the Taiwan Strait that could led to conflict, and having previously suggested that Taiwan policy language could be negotiated within broader trade talks with China, Trump has introduced a degree of ambiguity that risks blurring long-standing US commitments and deterrence signals. Beijing, ever attuned to shifts in Washington’s rhetoric, is reading these signals closely, and may interpret them as hesitation rather than strategy.
These statements are not the only mixed signals being sent. In September, Trump declined to approve a package of US$400 million in Taiwan military aid. In July, Taiwanese President Lai Ching-te’s planned transit through the US was quietly downgraded, with Washington declining to approve stopovers in US cities that Taipei had proposed en-route to Latin America. Instead, Lai’s team held a brief, closed-door meeting with US officials in Alaska—a far cry from the higher-profile engagements afforded to his predecessors. The shift reflects Washington’s caution amid efforts to stabilise ties with Beijing ahead of a US–China leaders’ meeting at the end of October. While the Alaska talks allowed working-level exchanges to continue, the optics signalled restraint: a return to managing Taiwan relations through discretion rather than display.
Taiwanese public opinion reflects this growing unease. Earlier this year, a Taiwan Public Opinion Foundation (TPOF) survey found nearly two-thirds of respondents were initially unconcerned about US–Taiwan ties deteriorating during Trump’s second administration.
But by October, sentiment has shifted: a plurality now views the US president as capable but unwilling to defend Taiwan.
The US continues to possess formidable military capabilities—it retains overwhelming power projection, intelligence reach and logistical depth—even if China’s rapidly modernising forces are steadily narrowing that advantage. Regarding US power and a possible Taiwan conflict, Trump has said: ‘we have the best of everything, and nobody’s going to mess with that. And I don’t see that at all with President Xi [Jinping].’ In praising US military strength while simultaneously downplaying the risk of a crisis and emphasising his good personal rapport with Xi, Trump projects confidence without commitment. Because what matters more is whether Beijing believes Washington would actually use that power in a crisis. If the US is seen as unwilling to bear the political or economic costs of intervention, its deterrent effect weakens, even if the weaponry remains in place.
Trump’s new ‘reciprocal’ tariffs have also deepened uncertainty in Taiwan. A sweeping 32 percent tariff (scaled down to 20 percent) has rippled through Taiwan’s export-reliant economy, sparking domestic partisan disputes. The Lai administration tried to frame the tariffs as a painful but necessary push toward diversifying Taiwan’s economy. The opposition party, meanwhile, argued the tariffs expose Taiwan’s dangerous over-reliance on the US market and the limits of the Washington–Taipei relationship.
Polls show the Taiwanese public split but pragmatic: they support emergency relief packages, yet are increasingly frustrated over their country’s economic vulnerability to shifting US politics. The semiconductor sector illustrates the paradox. Washington’s selective exemptions, particularly for firms such as TSMC investing in US fabrication plants, mitigate some of the tariff pain while binding Taiwan even more tightly into the US’s industrial strategy. In effect, US policy now both draws closer and constrains Taipei, reinforcing dependence while also claiming to promote resilience.
This transactional dynamic is reshaping the relationship. Under Trump, alliances are instruments of leverage, not expressions of shared values. Taiwan’s partnership with the US is being reframed less as a democratic bond and strictly as a component of the US’s broader relationship with China—something that can be priced, negotiated or withheld. For Taipei, that shift introduces strategic risk: a security partner that remains indispensable, but increasingly conditional.
The implications stretch beyond Taiwan. If Washington’s credibility erodes in Taipei, it reverberates through Tokyo, Canberra and other Indo-Pacific capitals that calibrate their deterrence postures and sense of security around US commitments. Ambiguity, long a deliberate feature of the US’s Taiwan policy, now looks less like strategy and more like drift.
Taiwan will likely continue to hedge by strengthening domestic defence, deepening cooperation with Japan and Australia and courting more European engagement. Yet the deeper question remains whether the US, under an administration that prizes transaction over trust, can still be counted on when it matters most. For Taiwan, the US’s reliable hard power may endure, but its promise to use it, if needed, feels increasingly negotiable.
