Canadian Prime Minister Justin Trudeau denounced President Donald Trump for launching a trade war with his country, saying that he won’t back down from a tariff fight with the United States.

“Today, the United States launched a trade war against Canada. At the same time, they’re talking about working positively with Russia, appeasing Vladimir Putin — a lying, murderous dictator. Make that make sense,” Trudeau said in Ottawa.

“Canadians are reasonable and we are polite, but we will not back down from a fight, not when our country and the well being of everyone in it is at stake.”

Trudeau pledged relief to Canadian workers caught in the trade war’s crosshairs, and told the American people that his quarrel was not with them.

“We don’t want this. We want to work with you as a friend and ally, and we don’t want to see you hurt either, but your government has chosen to do this to you,” he said.

Trudeau reserved his bluntest remarks for the president.

“It’s not in my habit to agree with The Wall Street Journal, but Donald, they point out that even though you’re a very smart guy, this is a very dumb thing to do,” Trudeau said. “We two friends fighting is exactly what our opponents around the world want to see.”

The prime minister lauded his at-times productive partnership with Trump dating to 2016 — including a renegotiated free-trade deal that Trump once called the “fairest, most balanced, and beneficial trade agreement we have ever signed into law.”

Still speaking directly to Trump, Trudeau urged a different tack:

“We have done big things together on the world stage, as Canada and the U.S. have done together for decades, for generations, and now we should be working together to ensure even greater prosperity for North Americans in a very uncertain and challenging world.”