TORONTO — Despite an already frayed relationship between the United States and Canada, President Donald Trump recently abruptly ended trade talks with the Great White North and imposed a 10% tariff on it. The move came after the province of Ontario aired a television ad in late October that used clips from a 1987 anti-tariff radio address by former President Ronald Reagan. A furious Trump dismissed the spot as “fraudulent” and “misleading.”

The Trump administration’s spat with Canada’s most populous province reflects an increasingly crumbling bilateral relationship. Tensions have risen for months between the mercurial Trump and Canada’s technocratic prime minister, Mark Carney, a former central bank official and financial services executive.