The U.S. Chamber of Commerce, the nation’s largest business group and customarily a close ally of President Donald Trump’s Republican Party, is launching a campaign on Monday to oppose Trump’s trade tariff policies.

With some of America’s tightest trading partners imposing retaliatory measures, Trump’s approach to tariffs has unsettled financial markets and strained relations between the White House and the Chamber.

The new campaign, detailed first to Reuters, is an aggressive effort by the business lobbying giant. Using a state-by-state analysis, it argues that Trump is risking a global trade war that will hit the wallets of U.S. consumers.

“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, which has 3 million members, historically has worked closely with Republican presidents and praised Trump for signing business tax cuts in December. But mounting trade tensions have opened a rift with the president.

Trump has implemented billions of dollars in tariffs targeted at China, Canada, Mexico, and the European Union, saying such moves are needed to offset trade imbalances.