Late Thursday night, President Trump took to Truth Social to reignite trade tensions with Canada, declaring all talks with America's northern neighbor will cease.

"ALL TRADE NEGOTIATIONS WITH CANADA ARE HEREBY TERMINATED," he wrote in all caps in a message posted at 11:15 pm ET.

It was a move, Trump says, spurred by a new ad produced by the government of Ontario that features Ronald Reagan to slam the president's trade approach.

This is far from the first up and down when it comes to Canada — the world's top recipient of US exports and the second largest trading partner overall — since Trump took office in January.

In fact, according to Yahoo Finance's count, this is at least the third instance of Trump threatening to end talks.

This June, the focus was on the issue of digital service taxes, which led Trump to write he was "hereby terminating ALL discussions on Trade with Canada."

By July, Trump said it was the Middle East that was making it "very hard for us to make a Trade Deal" with Canada.

Trump's previous threats were seen in the end as more about extracting concessions — with some success — instead of signaling any permanent end to talks.

This week's threat is also just the latest twist in a fraught nine-month relationship between Trump and a succession of two Canadian prime ministers.

It comes as all sides expect plenty more talks to be in the offing between now and a key deadline of next summer when the United States-Mexico-Canada Agreement (USMCA) trade pact is up for renewal.

That larger context — and Trump's history of threats that are ultimately short-term — might help explain the muted market reaction to Trump's message. All three indexes opened in the green on Friday morning, more focused on inflation data than this latest trade skirmish.

Trump's latest post was spurred by a new ad set to air during the upcoming World Series, which has a US and a Canadian team squaring off.

The minute-long message from the government of Ontario uses anti-tariff remarks that Ronald Reagan delivered in a 1987 radio address to argue against current trade barriers.

In the ad Reagan is heard saying that, as a result of tariffs, "markets shrink and collapse, businesses and industries shut down, and millions of people lose their jobs."

Trump declared the ad "fake" and called it interference in the US, even as the ad used selected comments from a longer Reagan speech but doesn't appear to have altered them.

A spokesperson for Ontario Premier Doug Ford defended the ad, telling CBC news that "the commercial uses an unedited excerpt from one of President Reagan's public addresses, which is available through public domain."

It’s official: Ontario’s new advertising campaign in the U.S. has launched.

Using every tool we have, we’ll never stop making the case against American tariffs on Canada. The way to prosperity is by working together.

Watch our new ad. pic.twitter.com/SgIVC1cqMJ

— Doug Ford (@fordnation) October 16, 2025

It's also just the latest rationale Trump has used this year to discuss cutting off talks.

Trump came into office and claimed on his first day in office that "Canada is a very bad abuser." He followed that up with tariffs, which largely went into effect in April, including 25% blanket duties as well as new steel and aluminum tariffs.

As negotiations for a de-escalation dragged on this summer, Trump abruptly (and in the end briefly) ended talks.

The issue in June was a planned Canadian implementation of a digital service tax targeting major US technology firms.

Trump called that tax a "blatant attack" as he cut off talks. His threat also got immediate results with Canadian Prime Minister Mark Carney delaying the tax's implementation within days.

By July, Trump had a new rationale and said it was the Middle East that would make it "very hard for us to make a Trade Deal" with Canada.

That threat bore less fruit for Trump, with Canada going ahead this September with its plan to back statehood for Palestine.

And in between the threats, Trump and Carney have had repeated and often friendly in-person meetings.

There was a May gathering in the Oval Office soon after Carney took office and another largely cordial meeting earlier this month.

The largest context is, of course, the challenging renewal of USMCA, which is required to be completed in about 10 months time.

That's the most economically significant piece of the back and forth because that pact, signed during Trump's first term as a replacement for the North American Free Trade Agreement (NAFTA), allows a wide array of goods to pass across the border duty-free.

Carney himself recently estimated that USMCA means that, for now, over 85% of Canada-U.S. trade continues to be tariff-free, blunting the effects of Trump's current 35% "blanket" tariffs.

Carney estimates that the overall effective tariff rate on Canadian goods remains a low 5.6%, for now at least.

Ben Werschkul is a Washington correspondent for Yahoo Finance.

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