Canada would likely impose its own tariffs on U.S. goods if they're levied here, meaning consumers on both sides of the border could feel pain.

For some in the car industry, the uncertainty surrounding a US-border trade war is almost worse than the tariffs themselves.

“Ground zero for the impact of a 25% tariff in automotive is Detroit-Windsor,” Volpe said. "All of these companies getting hit with a tariff when it crosses the border means all of them will ...