The US Supreme Court dealt a significant blow to former President Donald Trump by declaring his tariffs illegal, asserting that he did not possess the legal authority to impose such measures. This ruling comes after a lower court had already deemed the tariffs unlawful, marking a critical moment in the examination of presidential powers concerning trade regulations. The Chief Justice, John Roberts, and a 6-3 majority agreed that Trump’s application of the International Emergency Economic Powers Act (IEEPA) to impose tariffs was indeed an overreach of presidential power.

The court highlighted that the IEEPA, originally enacted in 1977, allows a president to regulate trade only during a national emergency. However, it was determined that Trump’s actions to levy high tariffs on imported goods were executed without the declaration of such an emergency, rendering his actions not only controversial but fundamentally illegal. The implications of this ruling could set a precedent for limiting executive power in trade negotiations and economic policy, especially in future administrations.

In the context of revenue generation, it was noted that despite the court's ruling, the tariffs had produced approximately $200 billion in revenue for the US in the fiscal year 2025. This raises questions about the economic impact and the future of tariff strategies in light of legal and constitutional challenges. The ruling not only affects Trump's legacy but could have lasting effects on how future presidents approach tariff-related policies and economic emergencies.