As the next US president threatens steep tariffs, the country’s two largest trading partners steel themselves for another rocky ride

Stone-faced as he stared into a gaggle of cameras on Tuesday, the leader of Canada’s largest province laid bare how it feels to be America’s northern neighbour and closest ally this week.

“It’s like a family member stabbing you right in the heart,” said Ontario’s premier, Doug Ford. A day before, president-elect Donald Trump had pledged hefty tariffs on Mexico and Canada, the US’s two largest trading partners. “It’s the biggest threat we’ve ever seen … It’s unfortunate. It’s very, very hurtful.”