The U.S. Chamber of Commerce, the nation’s largest business group and traditional ally of the Republican Party, has launched an aggressive campaign attacking Donald Trump’s trade tariffs. The president has implemented billions of dollars in tariffs targeted at China, Canada, Mexico, and the European Union, which in turn have have placed their own retaliatory penalties on U.S. goods such as bourbon and Harley-Davidson motorcycles. The Chamber warns that Trump is risking a global trade war that will make ordinary Americans poorer. “The administration is threatening to undermine the economic progress it worked so hard to achieve,” said Chamber President Tom Donohue in a statement to Reuters. “We should seek free and fair trade, but this is just not the way to do it.” The Chamber, a powerful group with three million members, previously praised Trump for signing business tax cuts in December.