The announcement that President Trump was raising tariffs on all US imports to 15% — hours after the Supreme Court struck down his previous tariff authority — did not merely represent a new policy decision. It marked the beginning of a new era of US trade uncertainty, one defined by escalating legal battles, shifting international alliances, and a president determined to press his trade agenda regardless of judicial or diplomatic resistance.
The mechanism Trump used — Section 122 of the Trade Act of 1974 — is technically limited in duration, providing only 150 days of authority before congressional involvement is required. But those 150 days are enough to cause significant disruption to global supply chains, long-term investment decisions, and diplomatic relationships. The administration has said it will use the window to develop new legal frameworks for tariffs, suggesting the uncertainty is designed to be a feature rather than a bug.
European leaders responded with a combination of alarm and determination. Germany’s Merz called for a coordinated EU response and warned that tariff unpredictability was acting as economic poison, while France’s Macron framed the moment as a test of democratic values. Both leaders signaled that Europe would not passively accept the terms of Trump’s trade policy without a fight.
The UK’s predicament encapsulates the broader challenge facing US trade partners. Having negotiated what it believed was a stable 10% tariff arrangement, Britain found that arrangement superseded overnight. Business leaders warned of the damage to trade relationships and called for the kind of certainty that allows long-term investment and planning. The message from Washington, however, was that certainty was not on offer.
Domestically, Trump’s broadside against the Supreme Court added a constitutional dimension to an already fraught situation. His personal attacks on justices — including his own nominees — alarmed legal scholars and raised questions about the health of American democratic institutions. With 90% of tariff costs falling on American businesses and consumers, and legal battles ahead on multiple fronts, the era of trade uncertainty that began this weekend shows no sign of resolving soon.