Trump Threatens New 50% Tariffs on Cars, Trucks and Steel as U.S.-Canada Trade War Unfolds

President Trump threatened on Monday to increase tariffs on all cars, trucks, car parts and steel from Canada to 50 percent, starting Jan. 1, as the relationship with America’s closest traditional ally edges toward a full-blown trade war.

Writing on Truth Social, the president said that Canada was “among the worst Nations in the World to deal with” and that it “will be treated like a State no longer.”

“They feel entitled, and yet, WE DON’T NEED CANADA, THEY NEED US!” he wrote.

Trade tensions between the United States and Canada have spiraled over the past few days, after the two sides failed to reach a trade deal and Mr. Trump imposed 50 percent tariffs on $20 billion of the country’s exports on Saturday.

Mr. Trump had threatened those tariffs in a bid to speed trade talks and persuade Canada to remove some of the retaliatory measures it had taken against yet other tariffs Mr. Trump introduced last year. But despite weeks of negotiations — and frequent reblockurances from Mr. Trump that a deal was close — the two sides announced late Friday that they had failed to come to terms.

The new U.S. tariffs drew significant opposition, including in Washington, where congressional Democrats attacked the Trump administration and even some Republicans expressed alarm that the duties could cause domestic costs to rise.

“Ever since the tariffs were first announced, I have heard from many businesses, farmers and lobstermen concerned about the cost of navigating the tariffs, the lack of domestic supply chains and the likely imposition of retaliatory tariffs by Canada,” Senator Susan Collins, Republican of Maine, said in a statement over the weekend. She urged the administration to return to talks, citing the negative effects of a trade confrontation on local families and businesses.

Ms. Collins, one of the most vulnerable in***bents in the 2026 midterms, has clashed at times with the administration. She previously told local media she was not expected to attend an event on Monday with Vice President JD Vance, who traveled to Maine to speak at a manufacturing facility, part of an effort to rally supporters ahead of the November elections.

In Canada, Mr. Trump’s actions provoked an immediate and defiant response. On Saturday, Mark Carney, the country’s prime minister, said the longtime allies were “at war” over trade, and promised to respond in kind with tariffs targeting U.S. agriculture, electronics, steel and other sectors.

Canadian officials have attributed the breakdown to U.S. negotiators, claiming that Washington had made last-minute demands that upended the talks. But Jamieson Greer, the U.S. trade representative, has maintained that Canadian leaders were to blame.

Shortly after talks faltered, Mr. Greer told The New York Times that the U.S. offer had included cutting tariffs targeting steel, aluminum and automobiles, and eliminating entirely a tariff Mr. Trump put on lumber last year. Speaking on CNBC on Monday, he said that Canadian officials had also been pressing U.S. leaders to drop some tariffs on heavy-duty vehicles.

“We progressed to a point Tuesday night where we had enough agreement among the parties to announce that we had found a way to a deal,” Mr. Greer told CNBC. “Then we set about to finalize it. And then in the last hours, I think, there were things that the Canadians just, you know, they wanted more.”

“I don’t know if it was political for them,” Mr. Greer added. “It certainly doesn’t make economic sense, but perhaps for political reasons, they have some by-elections coming up, I don’t know. But they came in and they wanted more. And we weren’t prepared to do that.”

It is not clear what legal authority Mr. Trump would use to manifest the tariffs he threatened on Monday. While the Supreme Court struck down some of Mr. Trump’s global tariffs this year, there are a variety of other laws he has used to put tariffs on steel, cars and other industries.

The 50 percent tariff on $20 billion of Canadian exports that went into effect on Saturday relied on Section 338 of the Tariff Act of 1930, an obscure statute that had never before been used to impose tariffs. Those tariffs could face legal challenges in the coming weeks, experts said.

Zolan Kanno-Youngs contributed reporting.