The Trump administration’s trade policies will hamstring the U.S.’s robust economic growth and threaten as many as 2.6 million jobs, according to a memo from the U.S. Chamber of Commerce’s top official on Thursday.

The memo—from Tom Donohue, the chamber’s chief executive, to his board of directors—followed news Thursday morning that President Donald Trump’s administration would make good on threats to apply tariffs to steel and aluminum imports from neighbors and allies, including Canada, Mexico and the European Union.

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