Announcement of tariffs on $20bn worth of US goods follows through on Mark Carney's vow to match US tariffs 'dollar for dollar'

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On Truth Social, however, the president shot down assertions that the US talks with Canada collapsed in part due a proposed trade deal that would have weakened French language protections.

“I would never interfere with Canadians speaking French!” he wrote. “In fact, I have never even thought of doing such a stupid thing. This lie was made up by a weak and ineffective Prime Minister in an attempt to gain political support, which he has totally lost, from the people of Quebec.”

Move is latest deterioration in trade relations between neighbors with historically strong economic ties

Donald Trump announced a new 50% tariff on automobiles and crucial raw materials from Canada, the latest deterioration in trade relations between the two neighbors with historically strong economic ties.

The US president said that the increased tariffs would start on 1 January 2027 on all cars, trucks, automobile parts and steel. He also derided the nation’s tariffs on American farmers, writing on social media that Canada has been “ripping off” the US “for years”.

Prime minister praised for rejecting US trade proposal as Trump shows little interest in retreating from dispute

• Are you a Canadian boycotting US products? We’d like to hear from you

Mark Carney said on Monday that while American negotiators saw the French language in Canada as an “irritant … in Quebec, these are rights,” days after receiving widespread praise from political leaders for rejecting a US trade proposal that many perceived as weakening the country’s Francophone culture.

The prime minister’s remarks came hours after the US president, Donald Trump, showed little interest in retreating from the spat, posting on social media that Canada had been “ripping off the United States of America for years” and threatening a swath of new, economically devastating tariffs on cars and trucks.

Breakdown shows Washington now prioritises its own interests over any semblance of shared economic ground

• ‘No more!!!’: Trump lashes out after US-Canada talks devolve into trade war

The calamitous collapse of trade negotiations between Canada and the United States is a warning to nations worldwide that pursuing any kind of dialogue with the current US administration is doomed at the outset, according to observers who say this recent episode indicates seeking a fair deal is futile.

Andrea Lawlor, an associate professor of political science at McMaster University in Ontario, said: “No matter the closeness of the historical relationship, the American administration has signalled that it now prioritises its interests above those of some sort of global economic coordination or harmony.

Audio recording of US vice-president apparently made at New York fundraiser and shared with Canadian Press

Leaked audio from a private event has reportedly captured the US vice-president, JD Vance, mocking Canada for apparently capitulating in a trade deal and taunting the prime minister, Mark Carney, for trying to “out-tough” Donald Trump.

The recording, which was reportedly made at a fundraiser and shared with the Canadian Press, comes in the last stretch of a difficult negotiation in which the US president has threatened to impose 50% tariffs on Canada.