Business leaders reacted with dismay to Trump’s statement Thursday that he would impose a new 5 percent tariff on all goods from Mexico beginning June 10 to force the Mexican government to take more aggressive actions to prevent Central American migrants from crossing its territory en route to the United States.

And a prominent member of the president’s party, Senate Finance Committee Chairman Charles E. Grassley of Iowa, blasted Trump’s move as “a misuse of presidential tariff authority and contrary to congressional intent.” Implementing the tariffs, he said, would “seriously jeopardize passage” of the United States-Mexico-Canada Agreement (USMCA)…

The president’s new tariff increases would “essentially blow up USMCA,” said Rufus Yerxa, president of the National Foreign Trade Council. “The economic impact will be devastating on both sides of the border.”

Hardest hit would be Detroit’s automakers, which have spread their supply chains across North America since NAFTA.