On Wednesday, Speaker Nancy Pelosi, Democrat of California, asked Mr. Trump to scrap or delay his State of the Union speech, scheduled for Jan. 29, until the government shutdown ends.
Democrats are unlikely to advance any legislation granting Mr. Trump more trade authority, either in the House, which they control, or in the Senate by providing votes for a bill.
“Giving him even more authority is a recipe for more economic chaos,” said Senator Ron Wyden of Oregon, the top Democrat on the Finance Committee, calling Mr. Trump’s approach so far “ineffective and ham-handed.”
Republican lawmakers have also expressed skepticism about expanding presidential tariff powers, including Senator Charles E. Grassley of Iowa, the chairman of the Finance Committee. Mr. Grassley has suggested that he will push forward with efforts to limit the unilateral trade authority of presidents. “We aren’t going to give him any greater authority,” he told reporters last week. “We’ve already delegated too much.”
Business lobbyists and free-market advocacy groups have begun a pressure campaign to dissuade rank-and-file Republicans from signing on as co-sponsors of Mr. Duffy’s bill, which they warn would undermine American competitiveness and upend the rules of international trade. The critics also warn that the law could violate Article I of the Constitution, which gives Congress the power to tax and set tariffs.
Some of those groups worry Republicans might support the bill simply to help Mr. Trump, without considering its long-term effects.
“Even though the likelihood of the passage of this thing is pretty low, it’s a dangerous marker for them to be throwing down,” said Brandon Arnold, the executive vice president of the National Taxpayers Union, a conservative advocacy group in Washington. “This is a complete game-changer, in a very negative sense, for the rules-based system of trade that the United States and the globe have benefited from.”