The United States signals new tax tightening: The 15% threshold is not the final limit

This development shows that United States trade policy is not cooling down, but is entering a more complex phase of adjustment, with greater uncertainty for the market and global supply chains.

No retreat after the court's ruling

The new turning point in United States tariff policy came after the Supreme Court of the United States ruled that the administration could not rely on the International Emergency Economic Powers Act (IEEPA) to impose a series of broad-based tariffs as before. Immediately thereafter, President Donald Trump announced a shift to imposing temporary broad-based tariffs under a different legal basis, initially at 10%, then raising the orientation to 15% on imports from all countries. Reuters reported that the 15% rate is the maximum level permitted in the initial phase under the newly invoked legislation.

Notably, the White House’s response was not defensive in nature. Rather than treating the Court’s ruling as a signal requiring relaxation, Washington used the legal gap created by the ruling to reconstruct its tariff instruments under a different framework. This indicates that the core objective of the policy remains unchanged: to continue maintaining tariffs as a trade and negotiation leverage tool.

If one looks only at the 15% figure, it may appear that Washington is self-limiting the new tariff level. In reality, this is primarily a temporary universal tariff during the transitional period. Reuters clearly stated that the mechanism being used is Section 122 of the Trade Act of 1974, which permits the imposition of tariffs of up to 15%, but only for 150 days unless extended through subsequent political procedures.

More importantly, at the time of announcing the 15% rate, Mr. Trump simultaneously stated that he would use the 150-day period to implement other “more lawful” tariff measures. Reuters reported that the United States administration is considering relying on other statutes to impose tariffs by product or by country, particularly in cases involving national security or investigations into unfair trade practices.

Therefore, the 15% threshold should not be understood as the final limit. In substance, it constitutes a baseline layer of tariffs to maintain pressure, while room for higher tariff increases remains in the hands of the White House.

The clearest signal that United States tariffs may exceed 15% appeared in the subsequent firm statement. Reuters and the Associated Press both recorded that Mr. Trump warned that any country attempting to “play games” with the Supreme Court’s ruling or to exploit that ruling to withdraw from previously reached trade commitments would face “much higher” tariffs under other trade statutes.

This is not merely a political threat. From a policy perspective, it clearly reflects Washington’s new strategy: instead of a single across-the-board tariff, the United States is shifting to a multi-layered model in which the universal rate serves only as the initial baseline, while higher rates may be selectively activated to exert pressure on specific partners. Reuters also reported that the United States administration may initiate additional investigations under Section 301, a legal step commonly used to pave the way for new rounds of tariff imposition.

Some countries may face a 15% rate or higher

Subsequent developments further reinforced the assessment that the 15% rate is not applied uniformly as a common ceiling. On February 25, Reuters quoted United States Trade Representative Jamieson Greer as stating that United States tariff rates on certain countries would increase to 15% or higher, although no specific partners were identified.

Earlier, Reuters also reported that higher tariff rates agreed upon in bilateral negotiations would continue to be maintained by the United States. Specifically, certain countries such as Malaysia and Cambodia may still be subject to a 19% rate, even though the new universal tariff is lower. This indicates that Washington’s new policy is operating under a “multi-layered” logic: at the same point in time, multiple tariff rates may coexist in parallel, depending on the agreement and negotiating position of each partner.

From a governance perspective, this represents a noteworthy shift. Previously, the United States tended to impose large-scale, broad-based tariffs to generate an immediate effect. Now, after the Court restricted its authority with respect to certain instruments, Washington is moving toward a more sophisticated approach: using a relatively broad baseline tariff to maintain pressure, while leaving open incremental “steps” of increases for each country, each product group, and each legal case file.

This model produces three simultaneous effects. First, it enables the United States to maintain negotiation leverage. Second, it makes it more difficult for partners to predict the actual tariff rate they may face. Third, it reduces the risk that the entire policy could be invalidated by a single judicial ruling, as the instruments have been dispersed across multiple legal bases. For this reason, observers assess that the Court’s ruling has not completely weakened the United States’ hardline trade strategy, but has merely compelled that strategy to change its form.

What markets fear most is not a number, but uncertainty

The most significant impact of the new developments does not lie in the 10% or 15% thresholds themselves, but in the prolonged uncertainty. Reuters reported that the latest tariff adjustment triggered negative reactions in financial markets; during the February 23 session, major Wall Street indices declined simultaneously as investors expressed concern about the forthcoming trade trajectory.

Import–export enterprises require stability to set prices, conclude contracts, calculate logistics costs, and organize supply chains. However, in the current context, they must not only account for the tariff rates in force, but also consider the possibility that those rates may change rapidly depending on legal developments or political negotiations. This lack of certainty increases hedging costs, making order expansion, inventory retention, and long-term investment more cautious.

Reuters also reported that U.S. Customs and Border Protection (CBP) will cease collecting the tariffs deemed unlawful under the International Emergency Economic Powers Act (IEEPA) by the Supreme Court from February 24, but this does not mean that tariff-related risks have ended. The new tariffs under Section 122 and other instruments continue to be applied, while the issue of refunds for previously collected duties remains unresolved.

For the United States’ major trading partners, particularly economies heavily dependent on exports to the United States, the current pressure lies not only in existing tariff levels, but also in the risk that agreements already concluded may still be overshadowed by new tariff policies.

Reuters reported that the European Parliament postponed its vote to ratify a trade agreement with the United States after Mr. Trump announced an increase of the temporary tariff to 15%. In that context, even partners that have reached consensus with Washington must reassess the actual scope of effectiveness of such agreements, particularly when the new baseline tariff may overlap with preferences or alter cost structures.

This demonstrates that international trade is facing a paradox: even where agreements exist, stability is not absolutely guaranteed, as United States tariff policy is becoming a more flexible and less predictable bargaining instrument than before.