If Trump does impose the tariffs in January, the auto industry would have little time to adjust, putting operating profits at risk for the automakers, Roeska said in an email. “A 25% tariff on Mexico and Canada would severely cripple the U.S. auto industry,” he said.

Trump, who takes office on Jan. 20, said he would impose a 25% tariff on imports from Canada and Mexico until they clamped down on drugs, particularly fentanyl, and migrants crossing the border, in a move that would appear to violate a free-trade deal.

In their initial round of responses to Trump's surprise announcement on Monday for a 25% tariff on imports from Canada and Mexico and an additional 10% levy on Chinese goods until they clamped down on illicit drugs and migrants crossing the border,

Put simply, tariffs are a tax on imports. Here's what Donald Trump did with them in his first term and how they impact the economy.