President Donald Trump‘s sweeping tariffs will be at the heart of a legal drama on Thursday when a federal appeals court weighs his authority to levy them via executive action. The full panel of judges on the United States Court of Appeals for the Federal Circuit will hear arguments in the Trump administration’s appeal of a May

On Thursday, the 11 judges on the U.S. Court of Appeals for the Federal Circuit in Washington, which typically specializes in patent law, are scheduled to hear oral arguments from the Trump administration and from the states and businesses that want his sweeping import taxes struck down.

The U.S. Constitution gives the power to impose taxes — including tariffs — to Congress. But lawmakers have gradually relinquished power over trade policy to the White House. And Trump has made the most of the power vacuum, raising the average U.S. tariff to more than 18%, highest since 1934, according to the Budget Lab at Yale University.