US-Taiwan relations in 2025; It sure was a turbulent year.

Written by Gerrit van der Wees.

Image credit: Public domain.

In a policy paper for the University of Nottingham Taiwan Research Hub in November 2024, we predicted that 2025 would be a turbulent year for Taiwan. It was, indeed, a turbulent year, with the turbulence even more severe – both in positive direction as in negative direction – than we expected.

Introduction.

US–Taiwan relations occupy a central place in Indo-Pacific security, global technology supply chains, and US–China strategic competition. Although Washington’s formal policy toward Taiwan has remained embedded in the Taiwan Relations Act (TRA) and the “One China” policy, the manner in which these commitments are articulated and operationalised has evolved over time. In 2025, these dynamics became especially visible. The year was marked by contradictory presidential statements, unprecedented congressional activism, and the codification of Taiwan’s strategic importance in US defence and security planning.

Presidential Rhetoric and Strategic Ambiguity.

Presidential rhetoric played a central role in shaping perceptions of the US commitment to Taiwan in 2025. In February, President Donald J. Trump declined to explicitly state whether the United States would prevent China from taking Taiwan by force, emphasising that he did not want to “comment on that”, preferring to remain non-committal. These remarks were widely interpreted as reinforcing traditional strategic ambiguity, yet their blunt delivery sparked concern among analysts and policymakers who feared they could weaken deterrence.

The non-committal February statements stood in contrast to reassurances issued by senior administration officials, including Secretary of State Marco Rubio, who reiterated US opposition to unilateral changes to the status quo and reaffirmed commitments under the Taiwan Relations Act. This divergence highlighted a recurring feature of 2025: ambiguity emanating from the White House, coupled with institutional reassurance from the foreign policy apparatus.

In October 2025, amid preparations for renewed diplomatic engagement with Beijing at the APEC Summit in Busan, South Korea, the State Department again emphasised continuity, stating that US policy toward Taiwan “has not changed” and remains grounded in longstanding frameworks.

While these remarks sought to stabilise regional perceptions, the contrast between the White House’s reluctance to commit and the State Department’s insistence on continuity underscored the administration’s balancing act between deterrence and diplomatic transactionalism. As it was, “Taiwan” did not come up in the meeting between President Trump and General Secretary Xi Jinping in Busan in early November 2025.

Congressional Assertiveness and Pro-Taiwan Legislation.

In sharp contrast to the presidential lack of commitment, Congress adopted an assertive posture toward Taiwan throughout 2025. Bipartisan concern over the PRC’s military modernisation and coercive tactics translated into legislative efforts aimed at strengthening Taiwan’s defensive capabilities and deepening institutional ties.

Foremost among these initiatives was the Porcupine Act (passed by the Senate on 11 December 2025), which sought to streamline arms transfers to Taiwan by elevating its status within the US export control and defence cooperation framework. The legislation reflected a growing consensus that Taiwan’s security depends on rapid access to asymmetric defence capabilities. Its overwhelming bipartisan support demonstrated Congress’s willingness to move beyond declaratory policy toward concrete deterrence measures.

Congress also advanced and enacted the Taiwan Assurance Implementation Act, mandating regular reviews of State Department engagement guidelines and reaffirming US commitments to Taiwan’s democratic governance and security. Taiwanese leaders publicly welcomed the law as evidence of enduring US support, underscoring its symbolic and practical importance.

Taken together, these legislative actions highlighted a consistently bipartisan congressional role in Taiwan policy.

The imposition of tariffs adds to the uncertainty.

The imposition of steep US tariffs by President Trump on Taiwanese exports in April 2025—initially set at 32 per cent and later negotiated down to 20 per cent—introduced an additional source of turbulence into the US–Taiwan relationship. From Taipei’s perspective, the tariffs were particularly jarring because they came amid heightened security cooperation, bipartisan congressional support for Taiwan, and repeated US assurances that Taiwan was a trusted economic and strategic partner.

The abrupt tariff announcement undercut that narrative, fuelling concerns within Taiwan that trade policy was being weaponised in ways that did not sufficiently distinguish between strategic competitors and close partners. Even after the reduction to 20 per cent, the episode generated uncertainty among Taiwanese policymakers and firms about the reliability and predictability of US economic engagement.

The sense of unease was exacerbated by the fact that Japan and South Korea—both key US allies and direct competitors with Taiwan in advanced manufacturing and technology sectors—were comparatively less disadvantaged by the new tariff regime.

With Tokyo and Seoul benefiting from the relatively lower tariff burdens, Taiwanese exporters faced a relative erosion of competitiveness in the US market. This asymmetry sharpened fears in Taipei that Taiwan was being implicitly grouped with trade targets rather than differentiated as a frontline partner in the US strategy toward Asia.

The National Defence Authorisation Act and Security Cooperation.

The fiscal year 2026 National Defence Authorisation Act (NDAA), debated and passed in late 2025, further entrenched Taiwan within US defence planning. The legislation authorised significant funding for the Taiwan Security Cooperation Initiative, expanded joint training and coast guard cooperation, and set aside funding for collaboration on uncrewed and counter-uncrewed systems.

On 18 December 2025, President Trump eventually ultimately signed the NDAA into law but expressed reservations about provisions he viewed as constraining executive authority in foreign and military affairs. These objections illustrated the broader tension between Congress’s desire to codify support for Taiwan and the executive’s preference for strategic flexibility.

Nonetheless, the NDAA’s Taiwan provisions represented a substantial deepening of defence cooperation. They signalled to both Taipei and Beijing that congressional support for Taiwan had become embedded in US military planning.

The National Security Strategy and Strategic Signalling.

The release, on 4 December 2025, of the National Security Strategy 2025 added another layer to the year’s turbulence. The document placed heightened emphasis on Taiwan’s strategic significance, particularly its role in regional deterrence and global semiconductor supply chains. Compared to previous iterations, the strategy adopted stronger language on the need to deter coercion in the Taiwan Strait while still avoiding an explicit security guarantee.

This approach reflected an attempt to reconcile competing pressures: reassuring allies, deterring China, and avoiding premature escalation. While the NSS clarified Taiwan’s importance within US grand strategy, it also reinforced ambiguity regarding crisis response, leaving unresolved questions about how rhetorical commitments would translate into action.

Taiwan’s Defence Posture: The US$40 Billion Special Budget.

A central development in Taiwan’s own security strategy came on 28 November 2025, when President Lai Ching-te announced a historic US$40 billion supplementary defence budget covering the period through 2033. This eight-year package, equivalent to NT$1.25 trillion (US$40 bln.), was framed as a decisive investment to safeguard Taiwan’s democracy, bolster asymmetric warfare capabilities, and deter a potential PRC attack. According to President Lai, the funds would support both major new arms purchases from the United States and the development of integrated defence systems such as the “T-Dome” air defence network, designed to counter aerial threats, including missiles and drones.

Lai’s announcement aligned with broader US strategic messaging urging Taiwan to take greater responsibility for its own defence, and US officials welcomed it as enhancing Taipei’s deterrent posture, but it was criticised by opposition members in Taiwan’s Legislative Yuan, who vowed to oppose the measures when they come up for a vote. The package also underscored Taipei’s commitment to raising defence spending to about 5 per cent of GDP by 2030 — an ambitious target aimed at strengthening domestic and allied contributions to regional security.

Regional and Strategic Implications.

The combination of US congressional support, strategic guidance frameworks, and Taiwan’s own defence initiatives helped shape regional reactions. US allies in the Indo-Pacific and beyond closely monitored these developments, often expressing support for deterrence measures while calling for careful management of cross-strait tensions. Conversely, China condemned expanded US–Taiwan cooperation and Taiwan’s significant defence investment as destabilising, framing such moves as “provocative” and contrary to its claims of sovereignty over the island.

Beyond the direct US–Taiwan Washington-Taipei dynamic, 2025 saw significant regional reverberations tied to Taiwan’s security. Notably, Japanese Prime Minister Sanae Takaichi’s 7 November 2025 parliamentary remarks suggested that a conflict over Taiwan could constitute a “survival-threatening situation” for Japan under its constitutional framework for collective self-defence, potentially justifying Japanese military involvement alongside US forces should a crisis threaten Japan’s own security (e.g., battleships or use of force in the Taiwan Strait).

These remarks signalled Tokyo’s intensifying concern about cross-strait instability and highlighted how Taiwan’s security has become inseparable from the strategic calculus of major U.S. allies in East Asia. The comments triggered a sharp diplomatic dispute with China, which demanded that Tokyo retract the remarks and warned they crossed established diplomatic red lines, while it was the remarks by China’s own consul-general in Osaka that really crossed red lines.

Conclusions.

The turbulence in US–Taiwan relations in 2025 stemmed from contrasting policy signals, institutional dynamics, and proactive defence measures. Ambiguous US executive rhetoric and the imposition of tariffs clashed with assertive congressional action, while strategic documents and domestic Taiwanese policy choices added layers of complexity to the bilateral relationship.

Taiwan’s unprecedented US$40 billion defence budget underscored its growing agency in shaping its own security, even as debates over US commitments and strategic ambiguity persisted. As a result, the developments of 2025 will likely continue to influence the trajectory of US–Taiwan relations and the broader security architecture of the Indo-Pacific.

As this article was going to press, on 28 December 2025, the Chinese armed forces, PLA, launched the most extensive military exercises until now, titled “Justice Mission 2025”, encircling the island and designed to keep “outsiders”  — read the US and Japan – away. This is a sign that 2026 will be even more turbulent than 2025.

Gerrit van der Wees is a former Dutch diplomat who currently teaches the history of Taiwan and US relations with East Asia at George Mason University in Fairfax, Virginia. He has also taught US relations with East Asia at the Elliott School for International Affairs at George Washington University in Washington, DC. 

This article was published as part of a special issue on ‘Review Taiwan 2025: Challenges, Continuities, and Change.’