Several key US allies including the United Kingdom, the European Union, Japan and South Korea are set to face higher trade-weighted tariffs under President Donald Trump’s new global duties, while rivals such as Brazil and China are poised to see significant reductions, according to analysis by Swiss-based trade watchdog Global Trade Alert (GTA).
The shift follows a 6–3 ruling by the US Supreme Court striking down the president’s use of the International Emergency Economic Powers Act (IEEPA) to impose sweeping tariffs.
In response, Trump announced a global tariff under Section 122 of the 1974 Trade Act, initially set at 10 percent and later raised to 15 percent. However, a White House fact sheet continues to list the rate at 10 percent, adding to uncertainty over implementation.
On a trade-weighted basis, the United Kingdom faces a 2.1 percentage point increase in its average tariff rate, while the European Union sees a 0.8 point rise, GTA said. Japan and South Korea face increases of 0.4 and 0.6 percentage points respectively.
By contrast, Brazil’s trade-weighted tariff rate drops 13.6 percentage points and China’s falls 7.1 points after the court invalidated IEEPA-based levies that had disproportionately targeted certain countries.
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Johannes Fritz, chief executive of GTA, said nations previously subject to dedicated IEEPA orders including China, Brazil, India, Mexico and Canada experienced the greatest relief.
“The Supreme Court struck down all of these, not just the reciprocal tariffs. So the countries that had the heaviest IEEPA exposure received the greatest relief,” Fritz said.
Some analysts argue the ruling disadvantages countries that had moved quickly to negotiate tariff ceilings with Washington following last year’s so-called “Liberation Day” tariffs.
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Sarang Shidore of the Quincy Institute said early deal-makers were “left holding the bag,” while countries that resisted US demands may feel vindicated.
Japan, for example, had secured a 15 percent reciprocal tariff rate in exchange for a US$550 billion investment pledge in the United States. Officials in Tokyo have indicated that investment commitments will proceed despite the legal shift.
The European Commission said it would seek “full clarity” from Washington, insisting that a previously agreed 15 percent tariff ceiling should remain in place.
In Asia, governments have largely adopted a cautious stance. China’s commerce ministry said it was conducting a comprehensive assessment of the ruling and urged Washington to cancel unilateral tariffs. India has reportedly postponed a planned visit by trade negotiators to Washington as it reassesses the situation.
South Korea’s trade ministry said it would pursue consultations to ensure that export conditions secured under its tariff agreement are not undermined. Singapore, which runs a trade deficit with the United States but was subject to baseline tariffs, said it was monitoring developments and seeking clarification on possible refunds.
Analysts say confusion now dominates the global trade landscape. Bilateral agreements negotiated under IEEPA may lack a clear legal basis, raising questions about whether the administration can reconstruct them under alternative authorities such as Section 301.
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“The actual impact on trade remains uncertain,” said Claudio Galimberti of Rystad Energy, noting that the legal framework underpinning earlier deals has effectively collapsed.
With allies facing higher effective rates and rivals seeing relief, the Supreme Court ruling has reshuffled the tariff landscape, leaving governments and businesses awaiting clarity on how — and at what level — the new duties will ultimately be enforced.
The latest tariff upheaval stems from trade measures first introduced by US President Donald Trump during his return to office in 2025. Framing the policy shift as necessary to correct trade imbalances and protect national security, the administration imposed sweeping “reciprocal tariffs” on a broad range of trading partners.
To implement those duties, the White House invoked the International Emergency Economic Powers Act (IEEPA), a statute traditionally used to address national security threats, sanctions and financial emergencies. The administration argued that trade deficits, fentanyl flows and border security concerns constituted a national emergency justifying tariff action.
Under IEEPA, countries such as China, Brazil, India, Mexico and Canada were subject to additional, country-specific tariff orders. Meanwhile, US allies including the United Kingdom, European Union, Japan and South Korea negotiated tariff ceilings often around 10 to 15 percent in exchange for investment pledges or trade concessions.
However, in a 6–3 decision, the US Supreme Court ruled that the president had wrongfully used IEEPA to impose broad-based tariffs, finding that the law did not grant authority for such sweeping trade measures. The decision invalidated not only the reciprocal tariffs introduced in April 2025 but also the additional country-specific levies tied to opioids and border security concerns.
In response, Trump shifted legal footing and introduced a global tariff under Section 122 of the Trade Act of 1974. Section 122 allows the president to impose temporary import surcharges of up to 15 percent to address balance-of-payments problems. The administration first announced a 10 percent baseline tariff, later stating it would rise to 15 percent, though official documents have reflected inconsistent figures, contributing to policy uncertainty.
The legal shift has reshaped tariff exposure across trading partners. Countries previously hit hardest under IEEPA-based measures have seen the largest effective reductions, while allies that negotiated early reciprocal deals now face relatively higher trade-weighted rates under the uniform Section 122 framework.
The ruling has also cast doubt on the legal durability of bilateral trade agreements negotiated under IEEPA authority. Analysts note that rebuilding those arrangements under alternative statutes such as Section 301 of the Trade Act would require fresh investigations and legal procedures, potentially prolonging uncertainty in global trade flows.
The episode underscores broader tensions over executive authority in US trade policy and highlights how legal constraints can rapidly alter the balance of economic advantage among trading partners.
