President Donald Trump called out four high-ranking GOP senators in a blistering online barrage early Wednesday, piling pressure on those tempted to push back against his impending tariffs against Canada. Senator Tim Kaine (D-VA) introduced a resolution to terminate the emergency declaration, and while the vote is largely symbolic, several Republican defections would carry political weight. Senators Susan Collins (R-ME) and Rand Paul (R-KY) have expressed support for Kaine’s motion, with Collins calling the tariffs a “huge mistake.”

President Trump is pressuring former Senate GOP Leader Mitch McConnell (R-Ky.) and other Republicans he’s labeled “disloyal” in the upper chamber to vote against Democrats’ resolution to bar his emergency declaration to impose tariffs on Canada. In a post to Truth Social early Wednesday, Trump willed the senators to “hopefully get on the Republican bandwagon, for a change, and fight the Democrats wild and flagrant push to not penalize Canada for the sale, into our Country, of large amounts of Fentanyl, by Tariffing the value of this horrible and deadly drug in order to make it more costly to distribute and buy.”

Not all of those senators have publicly committed to backing the joint resolution, but Trump’s post indicates that he’s nervous about them doing so. Sen. Tim Kaine (D-Va.) is trying to force a vote on a joint resolution to end the national emergency Trump declared to impose sweeping tariffs on America’s northern neighbor earlier this year. That declaration claimed authority under the International Emergency Economic Powers Act and cited the “extraordinary threat posed by illegal aliens and drugs, including deadly fentanyl” — but will also hike prices for American consumers, according to the Virginia Democrat. “More than 96 percent of fentanyl interdicted at our borders is coming from Mexico and less than 1 percent from Canada,” Kaine noted in a Washington Post op-ed last week.