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.

President Donald Trump has announced a flurry of trade activity ahead of Friday's official start of his new tariffs regime — executive actions including 50% tariffs on Brazil, a 15% tax on American imports from South Korea and an end to exemptions for imported goods worth less than $800.

The US is seeing increased tariffs income, but there are signs of some countries diverting trade from America.