In a single ruling, the Supreme Court fundamentally altered the legal landscape of Trump’s trade policy — and in a single Truth Social post, Trump made clear that the change would have minimal practical effect. The court struck down his IEEPA tariff authority; within 24 hours, he had invoked a new legal basis and raised tariffs by an additional 5 percentage points. The ruling changed everything legally and nothing practically.
Section 122 of the Trade Act of 1974 is the vessel Trump has chosen for his trade policy’s second act. It permits tariffs up to 15% for 150 days — a timeframe the administration frames as a bridge to new, legally durable mechanisms. Whether those mechanisms can be developed and deployed within 150 days, and whether they can withstand the kind of judicial scrutiny that felled the IEEPA approach, remains deeply uncertain.
The international response to the tariff hike was sharp. Germany’s Merz announced a coordinated European push back against US tariff policy and warned of the economic damage caused by constant uncertainty. France’s Macron offered a defense of judicial checks on executive power that was both philosophically pointed and diplomatically loaded. European capitals are no longer willing to simply absorb each new tariff announcement without a coordinated response.
The UK’s experience illustrates the particular challenge facing US trading partners who believed they had reached agreements with the administration. A previously negotiated 10% tariff rate was rendered moot by the 15% announcement — a reminder that deals struck with the current US government come with no guarantee of permanence. British business groups called the situation “bad for trade” and damaging to economic growth.
For Trump, the episode has reinforced both his determination and his isolation. Having attacked his own Supreme Court nominees, collected $130 billion in tariffs that were primarily paid by American consumers, and now invoked a never-before-used legal provision, Trump is pressing his trade war with undiminished energy. Whether the courts, Congress, or the economic realities of a trade war will ultimately constrain him remains the defining question of his trade legacy.