11:01 AM EDT, 04/01/2025 (MT Newswires) -- A growing bipartisan cohort of U.S. senators is poised to challenge the White House's justification for imposing tariffs on Canadian goods, in what could be the most significant Republican rebuke to U.S. President Donald Trump of his administration's second term, The Globe and Mail newspaper is reporting Tuesday.

It noted senators are expected to cast their votes Tuesday on a resolution in the Republican-controlled chamber seeking to terminate the national emergency the White House declared over illicit fentanyl flowing from Canada into American territory. Trump declared the emergency at the northern border in order to unlock special executive powers that allowed him to bypass congressional approval of the tariffs.

Republican Senator Susan Collins' office confirmed to The Globe and Mail on Tuesday morning that the Maine senator would support the resolution, which was introduced by Virginia Senator Tim Kaine, the 2016 Democrat nominee for vice-president. Speaking with reporters in Washington on Monday, Collins cited several examples of how deeply integrated Maine's economy is with Canada's, and expressed skepticism about whether the fentanyl flows across the border were significant. "Canada is not the problem," she said.

Tuesday's reporte noted the resolution already has the support of at least one Republican -- Kentucky Senator Rand Paul, who just last week added his name to the list of cosponsors. Paul has been outspoken about the need to rein in emergency powers and is a staunch supporter of free markets. Ahead of the vote, Politico reported that Republican Thom Tillis, of North Carolina, would support the resolution, and that Republican Senator Chuck Grassley, of Iowa, was undecided.

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