WASHINGTON (AP) With President Donald Trump’s so-called “Liberation Day” of tariff implementation fast approaching, Senate Democrats are putting Republican support for some of those plans to the test by forcing a vote to nullify the emergency declaration that underpins the tariffs on Canada.

Republicans have watched with some unease as the president’s attempts to remake global trade have sent the stock market downward, but they have so far stood by Trump’s on-again-off-again threats to levy taxes on imported goods.

Even as the resolution from Democratic Sen. Tim Kaine of Virginia offered them a potential off-ramp to the tariffs levied on Canadian imports, Republican leaders were trying to keep senators in line by focusing on fentanyl that comes into the U.S. over its northern border. It was yet another example of how Trump is not only reorienting global economics, but upending his party’s longtime support for ideas like free trade.

“I really relish giving my Republican colleagues the chance to not just say they’re concerned, but actually take an action to stop these tariffs,” Kaine told The Associated Press in an interview last week.

Kaine’s resolution would end the emergency declaration that Trump signed in February to implement tariffs on Canada as punishment for not doing enough to halt the flow of illegal drugs into the U.S. If the Senate passes the resolution, it would still need to be taken up by the Republican-controlled House.

A small fraction of the fentanyl that comes into the U.S. enters from Canada. Customs and Border Protection seized 43 pounds of fentanyl at the northern border during the 2024 fiscal year, and since January, authorities have seized less than 1.5 pounds, according to federal data. Meanwhile, at the southern border, authorities seized over 21,000 pounds last year.

Kaine warned that tariffs on Canadian goods would ripple through the economy, making it more expensive to build homes and military ships.

“We’re going to pay more for our food products. We’re going to pay more for building supplies,” he said. “So people are already complaining about grocery prices and housing costing too much. So you raise the cost of building supplies and products. It’s a big deal.”

Still, Trump has claimed that the amount of fentanyl coming from Canada is “massive” and pledged to follow through by executing tariffs Wednesday.

“There will never have been a transformation of a Country like the transformation that is happening, for all to see, in the United States of America,” the president said on social media Monday.

Republican leaders in the Senate have signaled they aren’t exactly fans of tariffs, but argued that Trump is using them as a negotiating tool.

“I am supportive of using tariffs in a way to accomplish a specific objective, in this case ending drug traffic,” Senate Majority Leader John Thune, R-S.D., told reporters last month. He said this week that his “advice remains the same.”

While Trump’s close allies in the Senate were standing steadfastly by the idea of remaking the U.S. economy through tariffs, others have begun openly voicing their dissatisfaction with trade wars that could disrupt industries and raise prices on autos, groceries, housing and other goods.

“I’m keeping a close eye on all these tariffs because oftentimes the first folks that are hurt in a trade war are your farmers and ranchers,” said Sen. Steve Daines, a Montana Republican.

Sen. John Kennedy, a Louisiana Republican, said he would prefer to see the U.S. and its trading partners move to remove all tariffs on each other, but he conceded that Trump’s tariff threats had injected uncertainty into global markets.

“We’re in uncharted waters,” Kennedy told reporters. “Nobody knows what the impact of these tariffs is going to be.”