Relief Without Certainty: Southeast Asia After the US Tariff Reset

Piper Stock | Indo-Pacific Fellow

Image sourced from ASEAN 2026 Host Media via Wikimedia Commons

When the United States (US) Supreme Court struck down many of Donald Trump’s 2025 “Liberation Day” tariffs, Southeast Asia appeared to catch a rare break. The ruling invalidated sweeping reciprocal duties that had targeted some of the region’s most export-dependent economies. Yet, the relief was short-lived. Within days, Trump announced a new global tariff of 15 percent on most goods entering the US, signalling that while the legal basis for earlier tariffs may have collapsed, the administration’s appetite for trade pressure has not.

For Southeast Asian economies, the ruling did not restore predictability. Instead, it reinforced a reality they have already been navigating for over a year: under the second Trump Administration, access to the US market is increasingly conditional, unpredictable, and subject to the whims of the current occupant of the Oval Office. The region may have avoided the most punitive tariff outcomes, but it remains deeply exposed to an unstable and transactional US trade strategy.

The 2025 Tariff Shock

Southeast Asia was among the region’s most heavily affected by Trump’s 2025 tariffs. Initial US proposals threatened duties as high as 40 to 49 percent on a number of ASEAN economies.

Rather than retaliating, most ASEAN governments pursued bilateral negotiations with the US. By October 2025, the majority had secured reduced tariff rates of around 19 to 20 percent. The final outcomes varied. Singapore faced tariffs as low as 10 percent, while Laos and Myanmar remained subject to rates of up to 40 percent. Major exporters such as Vietnam, Malaysia, Thailand, Indonesia, and the Philippines converged near the 19 to 20 percent mark, effectively levelling the playing field among regional competitors.

Bilateralism and the Transactional Turn

The negotiations revealed the extent to which tariffs had become a tool of leverage rather than protection. Trump openly acknowledged that the measures were designed to extract concessions, including greater access for American exports, commitments on regulatory reform, and tighter controls on Chinese transshipment – the practice of routing Chinese goods through third countries to avoid US tariffs.

Vietnam’s experience illustrates this dynamic. Initially threatened with a tariff rate of 46 percent, Vietnam secured a reduction to 20 percent after agreeing that transhipped Chinese goods would face a separate 40 percent duty. Indonesia similarly reduced its exposure from 32 to 19 percent in exchange for preferential market access for US firms.

Crucially, these arrangements lacked the legal certainty of traditional trade agreements. Analysts warned that the deals left significant room for reinterpretation and revision, particularly under an administration willing to use tariffs as a negotiating instrument. Smaller economies were especially cautious, aware that their treatment depended heavily on maintaining favourable relations with the US rather than adherence to a stable rules-based framework.

In effect, ASEAN states were adapting to a trade environment where access to the US market was negotiated country by country rather than governed by predictable multilateral rules. This represents a significant departure from earlier US trade strategy in the Indo-Pacific. For decades, US economic engagement in the region was instead centred on rules-based frameworks such as the Obama-era Trans-Pacific Partnership (TPP), which sought to establish common trade standards and deepen economic integration among Indo-Pacific economies. The TPP, which was never ratified by the US and Trump withdrew from during his first term, was widely viewed as part of a broader US strategy to strengthen economic ties with Southeast Asia while balancing China’s growing regional influence.

Relief or Reset? The Supreme Court Ruling

The Supreme Court’s decision to strike down many of the 2025 tariffs appeared, at first glance, to validate ASEAN’s cautious approach. In response, Trump introduced a new global tariff of 15 percent under Section 122 of the Trade Act, justified as a temporary measure to address the US trade deficit. These levies are scheduled to remain in effect for 150 days, though they could face legal challenges of their own.

The ruling introduced uncertainty over whether existing bilateral agreements would remain in force, as the legal basis for maintaining the 19 percent deals with countries such as Malaysia, Indonesia, and Cambodia remains contested.

Complicating matters further, China emerged as one of the immediate beneficiaries of the court’s decision. The ruling struck down both the baseline reciprocal tariffs and additional fentanyl-related duties that had applied broadly across Chinese exports. Although China will still face the new 15 percent tariff, exemptions for key electronics products and the temporary nature of the measure could narrow the gap between Chinese and Southeast Asian exporters.

If China ultimately secures more favourable treatment, even temporarily, the momentum behind supply chain relocation into Southeast Asia could slow.

Living With Conditional Access

The volatility surrounding US tariffs has wider geopolitical implications for Southeast Asia. For ASEAN states, many of which rely heavily on export-driven growth and stable access to global markets, this unpredictability complicates long-term economic planning and investment decisions. It also risks weakening confidence in the United States as a reliable economic partner, particularly in a region that has historically sought stability in its relationships with major powers.

Rather than aligning exclusively with either the US or China, ASEAN governments are expanding ties with a broader range of partners to hedge against geopolitical risk. Indonesia’s recent progress toward a Comprehensive Economic Partnership Agreement with the European Union reflects this trend. Its decision to join BRICS, alongside Thailand’s new role as a BRICS partner country, further illustrates Southeast Asia’s effort to broaden its economic partnerships. As uncertainty in US trade policy persists, ASEAN states may continue deepening economic ties with alternative partners, including the EU and middle powers such as Australia, Japan, and South Korea.

Piper is a fourth-year Bachelor of Laws and International Relations student at Griffith University. She currently works as a Federal Electorate Officer in the Australian Parliament, where she undertakes policy research, drafts parliamentary correspondence, and supports constituents on a range of federal matters. She also has professional experience in the legal sector as a Legal Administrator.

Piper is actively engaged in leadership and public service. She is a Board Member of the Griffith University Student Guild, a Gold Coast Mayor’s Student Ambassador, and a mentor for Political Science and International Relations students at Griffith University. She has also been recognised with the Griffith Business Leadership Award.

Through this fellowship, Piper hopes to combine her strong interest in the Indo-Pacific region with her professional experience to explore how domestic policy, diplomacy, and regional cooperation intersect in shaping Australia’s engagement with its nearest neighbours.

Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect those of Young Australians in International Affairs. All content is original, and no plagiarism has been used in the preparation of this article.