Communities on either side of the Canada-U.S. border braced for further economic fallout on Monday after trade talks collapsed and both countries moved deeper into a tariff fight.

Mayor Mike Bradley of Sarnia, a major Ontario border city and petrochemical hub, said the trade dispute would be a “job killer” for his community. The city is a major exporter of plastics, one of the product groups targeted by the latest U.S. tariffs.

He backed the federal government’s response, but he warned the supportive mood in his community could be tested once the full brunt of the tariff fight was felt.

“Everyone can be supportive at this stage of the game. When the pain really starts to unfold with job losses and industries being devastated, I think it’s going to be much harder to hold the Canadian public together,” he said, while appealing to other leaders to stand united.

Prime Minister Mark Carney has vowed a dollar-for-dollar response to the 50 per cent U.S. tariffs imposed on roughly $28 billion in Canadian goods following failed trade talks. Canada’s retaliatory tariffs are set to come into force on Sept. 8 and target sectors such as steel, dairy, pulp and paper, electronics and appliance.

Tensions escalated again Monday when U.S. President Donald Trump threatened to slap 50 per cent tariffs on Canadian vehicles and auto parts beginning Jan. 1. His threat also included steel, which is already subject to a 50 per cent tariff.

Those fresh threats raised concern in Windsor, the heart of Canada’s automaking industry. Mayor Drew Dilkens said the levies would cost jobs if imposed, but he hoped “sensible minds will prevail” before then.

Dilkens pointed to the upcoming U.S. midterm elections as a chance to highlight the potential consequences of a tariff dispute in swing states, such as neighbouring Michigan.

“This war by Donald Trump on Canada, its largest trading partner, will prove to be massively unsuccessful for the United States, but there will be casualties along the way if this goes on for any length of time,” Dilkens said.

Several Democratic governors of U.S. border states spoke against Washington’s response over the weekend.

Michigan Gov. Gretchen Whitmer said residents in her border state were “uniquely impacted” by the trade dispute, arguing tariffs drive up costs for families and businesses and threaten its auto manufacturers.

New York Gov. Kathy Hochul said the president was “needlessly picking fights” with U.S. allies.

This report by The Canadian Press was first published Aug. 24, 2026.