At the heart of the dispute is the International Emergency Economic Powers Act (IEEPA), which Trump leveraged to impose “Liberation Day” tariffs, including new levies on China, Mexico, and Canada earlier this year. While the administration argues these tariffs are necessary responses to extraordinary threats, such as the flow of fentanyl or persistent trade deficits, two federal courts have determined that Trump exceeded his lawful authority, reaffirming the power to levy tariffs remains a congressional prerogative and the emergency invoked by Trump when exercising IEEPA did not fit the situation he inherited as president.

The president’s lawyers warned the Federal Circuit’s 7–4 ruling, which found the tariffs unlawful, jeopardizes both ongoing trade negotiations and framework deals that have already been negotiated. They pressed for an expedited review, proposing Supreme Court oral arguments by early November—a rare request, reflecting what he claimed are existential stakes for American industry.

That decision cast “a pall of legal uncertainty over the President’s efforts to protect our country by preventing an unprecedented economic and foreign-policy crisis,” the Trump administration argued in its appeal, per ScotusBlog and Lawrence Hurley of NBC News. The administration’s lawyers warned “the economic consequences would be catastrophic” of the unwinding of Trump’s tariff regime.

Trump’s dire economic warning

Trump has amplified his message with public declarations that eliminating these tariffs risks devastating consequences for U.S. workers and manufacturers. “If you took away tariffs, we could end up becoming a third-world country,” Trump insisted at a recent White House press briefing, framing tariff protection as essential to economic security and leverage in trade talks.

The administration has been generating considerable revenue from the tariffs, with Morgan Stanley predicting a whopping $2.7 trillion haul over the next decade. If the Supreme Court waited to decide on the case until June 2026, Trump’s lawyers calculated, then between $750 billion and $1 trillion in tariffs may have been collected by then. Unwinding them “could cause significant disruption,” according to the White House, warning that previously agreed investments in the U.S. economy could also be unwound. American businesses, for its part, could be due for a $150 billion refund, Fortune previously reported.

Behind the headlines: economic and political realities

The debate has divided economists and business leaders. Experts note that tariffs have raised average household costs by over $1,300 a year—a regressive burden especially on low-income Americans—while lower-income households spend a bigger share of their money on imported goods. Conversely, tariff repeal could sharply reduce these costs, cutting the effective rate from 25% to just over 4%.

Manufacturing sectors like steel have benefited from tariff protection, but the broader economy has faced higher input prices, especially for automotive and electronics companies. Some economists characterize Trump’s gloom-and-doom warnings as exaggerated, predicting instead a painful adjustment and market volatility rather than outright catastrophe. Small businesses, meanwhile, have argued the tariffs threaten their financial survival and force difficult supply chain decisions.

Wider implications: Congress, courts, and global trade

The Supreme Court case could set crucial precedents on the balance between congressional and presidential power in trade. Legal scholars say the lower courts’ rulings reinforce constitutional checks and are wary of unlimited tariff authority under IEEPA. If the justices side with the appellate judges, tariff refunds and rapid supply chain reforms may follow, with broad implications for industry, investors, and consumers.

For Trump, the tariffs remain a core campaign and policy issue, connecting trade protection to promises of economic revival and geopolitical strength. As the nation awaits the Supreme Court’s decision, the outcome has the potential to reshape both economic policy and the boundaries of presidential power for years to come.

For this story, Fortune used generative AI to help with an initial draft. An editor verified the accuracy of the information before publishing.