Since the U.S. Supreme Court in February ruled that President Donald Trump lacked legal authority for his sweeping “Liberation Day” tariffs, Malaysia appears to be the first—and so far only—country to formally end its trade agreement with the Trump administration. Malaysian Trade Minister Johari Abdul Ghani told reporters in March that the deal “is not on hold. It is no longer there. It’s null and void.” Although the ministry subsequently claimed that he had “misspoken,” Johari later reaffirmed his statement on canceling the deal.

For his part, Trump has cautioned nations against making any changes to existing deals while his administration is actively seeking alternative means of exerting economic pressure, including sector-specific tariffs and Section 301 investigations over allegedly unfair trade practices. Indeed, Malaysia is now one of six Southeast Asian nations (the others are Cambodia, Indonesia, Singapore, Thailand, and Vietnam) to become a target of Washington’s Section 301 investigations into alleged violations related to manufacturing overproduction and forced labor. Last week, the Trump administration additionally singled out Vietnam as a priority target for a Section 301 investigation related to the protection and enforcement of U.S. intellectual property; Indonesia has been placed on the watchlist for similar concerns. Further retaliatory measures may now follow.

Fear of yet more retaliation by Trump is precisely the reason why the rest of Southeast Asia is unlikely to follow in Malaysia’s footsteps. At the same time, however, several U.S. allies and partners in the region now appear to be soft-pedaling tariff negotiations or quietly exploring how to renegotiate their deals now that the White House faces new legal constraints.

One such country is Vietnam. Vietnamese officials have publicly emphasized continued engagement on trade to forge a deal, with Trade Minister Le Manh Hung stating that Hanoi is “willing to increase purchases of U.S. goods” even as it quietly recalibrates its approach amid growing uncertainty. During Vietnamese leader To Lam’s recent visit to Beijing to meet with Chinese President Xi Jinping, the two leaders pledged to deepen economic integration between their countries by focusing on supply chains and expanding sectoral, industrial, and technological cooperation. Given that Trump had just announced his Liberation Day tariffs, the timing was significant.

Meanwhile, Thailand, a U.S. security ally, has gone mostly quiet since the Supreme Court ruling. Immediately after the announcement, Thailand’s opposition People’s Party blasted the government for having agreed to a 19 percent tariff rate last year, calling it a “diplomatic blunder” and underscoring how U.S. tariffs have become a flashpoint in Thailand’s volatile politics following the recent downfall of multiple prime ministers. In response to the court’s decision, the Thai Commerce Ministry noted that Bangkok was no longer obligated to negotiate or renegotiate any trade deals with Washington.

Although Thailand was seeking a new U.S. trade pact by mid-2026, there has been no official public comment since the Supreme Court’s ruling. Rather, Bangkok is now focused on countering a Section 301 investigation, where a written response to Washington is pending.

Indonesia, at least for now, is sticking to its tariff agreement with the United States. Perhaps regrettably for Jakarta, it signed the deal on Feb. 19, one day before the Supreme Court’s invalidation of Trump’s blanket tariffs. The uncertainty surrounding how the court’s decision will be implemented is creating angst among Indonesian officials. They still lack clarity on core operational details, such as which products qualify for tariff exemptions, how rules of origin will be applied, and whether goods incorporating inputs from China or other countries will face special restrictions. Without clear answers, Indonesia’s Trade Ministry and other government bodies cannot finalize local regulations, leaving the deal in a kind of policy limbo. In this sense, the agreement may still be in place, but it remains unfinished.

Domestic politics in Indonesia further complicate the picture. Although Indonesian President Prabowo Subianto commands a strong parliamentary majority, legislative ratification of the trade deal is not guaranteed. Lawmakers remain sensitive to public opinion, and the agreement has generated notable backlash among economists, civil society groups, and parts of the policy community. Ratification may therefore hinge on revisions, clarifications, or at least more effective political messaging. Prolonged U.S. ambiguity only further confuses the matter and may eventually push Indonesia to copy Malaysia’s outright rejection of trade deals with Trump.

Finally, neither the Philippines nor Singapore has responded publicly since the Supreme Court’s decision, suggesting that they are keeping quiet to avoid Trump’s wrath while they hope for a better deal. Manila, a formal U.S. treaty ally, is likely engaging Washington quietly through diplomatic channels to preserve defense and economic linkages while seeking clarity on how any revised tariff architecture might affect its export sectors and semiconductor-linked supply chains. It is also likely balancing its response carefully given ongoing efforts to deepen U.S.-Philippine security cooperation in the South China Sea.

Singapore, by contrast, is expected to adopt a highly technocratic and low-profile posture, consistent with its long-standing preference to avoid public disputes with major powers on trade. As a deeply trade-dependent economy and regional financial hub, Singapore’s likely priority is ensuring predictability and minimizing disruptions to transshipment flows and investment sentiment, even as it monitors whether broader U.S. tariff recalibration could spill over into financial services and high-tech sectors.

Taken together, Southeast Asia’s response to the Supreme Court ruling underscores a shared but uneven strategy of hedging rather than confrontation. Malaysia’s outright termination of its agreement is the exception so far, as most states in the region quietly adjust to a legal environment in Washington that has introduced more questions than answers. The result is a fragmented but generally cautious regional posture: Governments are neither fully disengaging from U.S. trade frameworks nor confidently advancing new agreements; instead, they are waiting to see how the Trump administration reconstructs its tariff toolkit following the Supreme Court shock. In this interim period, uncertainty itself has become the dominant policy variable shaping Southeast Asia’s economic diplomacy with the United States.