Trump says he will raise new global tariffs to 15% after hitting out at ‘terrible’ Supreme Court

British companies that spent weeks negotiating what appeared to be preferential access to the US market now face a sobering reality: those carefully secured deals may be worthless before the ink has dried. Within 24 hours of the Supreme Court striking down his emergency tariffs, Donald Trump not only reimposed levies through alternative legal mechanisms but raised them from 10 to 15 per cent, leaving UK officials scrambling to determine whether sector-specific carve-outs survive the restructuring. The whiplash reflects a deeper problem for any business attempting to plan around this administration's trade policy.

From favoured nation to legal grey zone

The Supreme Court's 6-3 ruling on Friday found that Trump lacked Congressional approval to impose tariffs under the 1977 International Emergency Economic Powers Act. The decision invalidated the so-called "reciprocal tariffs" programme that had extracted £98.4 billion from importers since April. Within hours, Trump invoked Sections 122, 232, and 301 of alternative trade statutes to impose a 10 per cent global tariff. By Saturday, he'd raised it to 15 per cent.

What remains unclear is whether the bilateral agreements negotiated under the now-defunct legal framework retain any force. UK government sources indicated they "expect" the country's privileged position to continue, according to official statements, but the government's own revisions tell a different story. An initial response referenced Britain enjoying "the lowest reciprocal tariffs globally." That phrase was quietly removed in an updated statement hours later.

Officials believe most preferential arrangements on steel, automobiles, and pharmaceuticals will survive, according to people familiar with the government's assessment. But belief is not certainty. Trump himself acknowledged that "some of them stand, many of them stand, some of them won't" when asked about existing trade agreements following the Supreme Court decision.

The fiscal pressure behind the legal manoeuvring

The administration faces a significant financial headache beyond the political embarrassment of a Supreme Court rebuke. Having collected £98.4 billion under tariffs now deemed unlawful, the US government potentially owes that money back to importers. That liability creates powerful incentive to maintain high collection rates through whatever legal authority survives judicial scrutiny.

Trump claimed the court "has been swayed by foreign interests" and predicted that countries "dancing in the streets" would soon regret their celebration.

The attack on judicial independence, offered without evidence, signals an administration willing to challenge constitutional norms to preserve revenue streams and political messaging around trade. The legal workaround Trump has chosen invites fresh challenges. Section 122 of the Trade Act allows temporary tariff adjustments but has rarely been used for blanket global levies.

Sections 232 and 301, concerning national security and unfair trade practices respectively, require specific findings that may prove difficult to defend when applied universally. Legal experts have already questioned whether these statutes can bear the weight Trump is placing on them.

Strategic paralysis for UK exporters

For British businesses, the practical effect is strategic paralysis. A pharmaceutical manufacturer that planned US expansion based on a 10 per cent tariff carve-out now faces 15 per cent levies with no clarity on whether negotiated protections apply. An automotive parts supplier that restructured supply chains to take advantage of preferential rates must now account for potentially invalidated agreements.

The five-month timeframe Trump initially suggested for the 10 per cent rate has already proven meaningless, given the jump to 15 per cent within a day. The president indicated his administration would use that period to conduct "various investigations necessary to put fair tariffs, or tariffs period, on other countries." The qualification "or tariffs period" rather gives the game away about the investigative rigour on offer.

The British Chambers of Commerce noted the Supreme Court decision did "little to clear the murky waters for business" around US tariffs.

William Bain, the organisation's head of trade policy, emphasised that bringing tariffs down "wherever possible" remains the priority, a diplomatic way of saying UK negotiators are working with an unreliable counterparty. What's striking about this episode is how quickly apparent victories have evaporated.

The UK government presented its initial 10 per cent rate as a diplomatic achievement, proof that Britain's bilateral relationship delivered tangible commercial benefits. Within weeks, that achievement exists in a legal grey zone, potentially superseded by blanket tariffs 50 per cent higher than the "privileged" rate officials celebrated.

The broader lesson extends beyond this specific tariff chaos. Any business or government treating bilateral agreements with this administration as stable planning assumptions is building on sand. The combination of legal vulnerability, presidential impulsivity, and fiscal pressure creates conditions where even signed deals carry minimal predictive value about future policy.

British officials will continue negotiating to preserve whatever preferential treatment they can secure. Businesses will hedge and adapt, because that's what they do. But the strategic calculation has shifted. Deeper economic integration with the United States under current political conditions means accepting that the terms can change overnight, through legal manoeuvres, presidential social media posts, or both. For a business community that prizes predictability above most other factors, that's not privileged treatment. That's exposure.