Canada is bracing for the possibility that former U.S. President Donald Trump, if re-elected on Tuesday, could quickly impose a sweeping tariff on all U.S. imports, potentially setting off a damaging trade dispute.

Canadian officials received no assurances in talks with several Trump allies ahead of next week's vote, CBC News has learned An official was privy to the details of these conversations.

Trump's proposal for a 10 percent global minimum tariff has caused more alarm in Ottawa than any other promise made by either U.S. presidential candidate.

To better understand how this might play out, Canadian officials consulted contacts who were part of Trump's Treasury and trade office, including some who would likely return to government if he wins.

Their concerns were not allayed.

“All indications are that former President Trump is determined to impose tariffs, and quickly,” said a Canadian official with insight into those talks.

“He believes in tariffs as a political tool.”

That official, who asked for confidentiality so as not to harm Canada-U.S. relations, stressed that it was not surprising that Trump's supporters would avoid offering such assurances now, in the midst of a tough election campaign.

It's not the only Trump policy that would impact Canada. His promise to deport millions of undocumented migrants could lead to humanitarian pressure as asylum seekers grow at the border with Canada.

By being vague about the details of his plans, Trump has allowed competing interpretations to prevail about exactly what he intends to do.

Deciphering Trump's Intentions

On the one hand, the co-chair of Trump's transition team rejected the idea that his tariffs would apply to everything. Howard Lutnick says they only affect certain products and are used as a negotiating ploy to force other countries to open their markets.

On the other side is reportedly Trump's former trade czar Robert Lighthizer tell people that there will quickly be flat-rate tariffs. He even wrote in his book about how he would shape the policy.

In his opinion, the tariffs should not only apply to all products – the 10 percent should actually increase every year until the US ends its chronic trade deficits, says Lighthizer, who has declared himself open to returning to government.

Canadian business groups that met with Lighthizer during his time in Calgary this year not You can also come away with peace of mind.

These details are important for Canada.

The estimated damage to Canada

There are a variety of estimates about the potential damage to Canada. A Washington think tank says Canada could lose almost half a point of its GDP, but others suspect the damage could be far worse, even a a devastating five percent Loss if the tariffs provoke an outright trade war.

“Canada will never have faced such a threat to its trade-related prosperity in its entire history as a country,” said Eric Miller, a Canadian-American trade adviser based in Washington.

So what is it: a flat rate? Or a surgical tool to steer certain productions back to the US and influence trade negotiations?

“It's possible that both are true,” said Christopher Sands, director of the Canada Institute at the Washington think tank Wilson Center.

For example, he can't imagine a tariff on Canada's largest export to the United States: oil. It would be tantamount to imposing a carbon tax, which is anathema to Republicans.

This is exactly the case that the Canadian government is preparing for if Trump wins: that sweeping tariffs on Canada would threaten inflation in the U.S., especially since a quarter of all Canadian exports to the U.S. are energy products.

So here's what Sands envisions: a quick announcement that tariffs will be imposed if Trump wins, via one of them several Laws already on the books.

“He could say on day one, 'I'm going to put a 10 percent tariff on everyone.' But I don’t think it will take effect (immediately),” Sands said.

Implementation would be gradual. Trump, meanwhile, would begin meeting with foreign leaders and demanding changes to their trade policies, Sands says.

In Sands' view, Trump might say, “'If you don't do what I want, I'll put a 10 percent tariff on all your stuff, or maybe I'll put a 10 percent tariff on this or that.'” Some of it will be some take time.

For example, the USA has a list of complaints with Canada on trade: from dairy import regulations to what counts as North American carto Canada Tax on tech giantsto its failure to stop deliveries of Goods produced in labor camps.

Whoever wins the White House, Trump or Kamala Harris, is expected to push for changes in these areas when the current continental trade deal comes up for review in 2026.

Pressure on the defense

Canada will also come under pressure to increase military spending. If Trump wins, there is a risk that this pressure will become even greater.

A defense strategist in the last Trump administration, Elbridge Colby, recently made the case for a possible leadership role if Trump wins again said CBC News He called on the president to consider economic threats if Canada does not take quick and meaningful action.

Sands says he can't imagine additional tariffs on defense spending. But he could envision the U.S. barring Canada-based companies from military contracts or restricting their access to sensitive technology, which could force companies to move production south.

Miller's advice to Canada is twofold.

What retaliation might look like

First, Canada should make itself as indispensable as possible through development critical mineral resourcesbuilding its defense and taking on difficult tasks related to managing international migration.

This, he said, would give Canada new influence in Washington.

His second piece of advice? Be prepared to play hard.

He would compile a list of business leaders close to Trump and prepare to hit their businesses with retaliatory tariffs.

“This is not about harming the United States,” Miller said. “It's about hurting the people around Trump who are in a position to tell him, 'You know, maybe we shouldn't do this.'”

Canada has already hinted at possible retaliation. Canada's Ambassador to Washington, Kirsten Hillman, warned this possibility at the Republican Summer Convention.

Of course, Canada would inevitably come away with bruises. A fight with the world's largest economy will be painful, especially a trade dispute in which the smaller party is much more reliant on cross-border sales.

Canada is buying less than 20 percent of US goods exports to the world, while the US buys more than 75 percent of Canada's total exports.

And that is one of the reasons mentioned above study Trevor Toombe of the University of Calgary warned that things could get ugly – such as an ugly five per cent loss in GDP – if a trade war broke out.

Of course, much of this could be moot if Trump loses on Tuesday.

With Kamala Harris as president, Canada would have inevitable trade disputes, such as those already mentioned, as well as the perennial timber dispute.

Asked what particular challenges they would expect under a Harris presidency, Canadian officials cited their ties to the tech sector in their home state of California and said they expected aggressive opposition to Canada's digital services tax.

For Canada, Miller characterized Harris' presidency as: “A much easier, more predictable government to deal with.”