The U.S. is set to impose new tariff rates on trading partners Friday when the deadline President Donald Trump set for countries to negotiate rates with the U.S. expires—with only nine countries announcing agreements with the Trump administration, far short of its goal of 90 deals in 90 days.

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.