A Trump win or a disputed result are Canadians' worst fears

Before every US presidential election, a few disgruntled Americans can be relied on to promise that they’ll move to Canada if the results don’t go their way.

Canadians watch US elections with close attention – and occasional horror – but they rarely expect many voters to make good on that vow. A few do make the move; most do not.

However, in recent weeks the political temperature in the US has mounted: senior Republicans have called for supporters to “guard” polling stations, and right-wing militias have openly called for armed revolt in the event that Donald Trump loses.

In Canada, fears are growing that the fallout from a contested vote could spill across the border.

Related: 'I'm moving to Canada': the cops, pop stars and athletes who made good on the threat

The spectre of unrest, trade disruption, and even violence is likely to have prompted frantic strategising among senior government officials, said Thomas Juneau, a professor of international relations and security studies at the University of Ottawa.

“We are absolutely at the point where we have to think about scenarios that … start raising really difficult questions for Canada,” said Juneau.

A contested election, or a second term of Trump where he begins making decisions that are bad for Canada, are both looking like plausible outcomes, he said.

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As one of the United States’ largest trading partners, Canada cannot afford to be caught off-guard. The two nations share the world’s longest undefended border and have highly integrated economies.

“There are few things that Canada does better than understanding the United States,” he said. “There is not a single department in the Canadian government, that doesn’t devote a considerable proportion of its resources and time to managing relations with the US. Folks in the Canadian government think about the relationship every day.”

The prime minister, Justin Trudeau, who has spent much of his tenure restraining any urge to overtly criticise Trump, has expressed cautious optimism about the upcoming election and downplayed fears of violence or disruption.

“I think we’re certainly all hoping for a smooth transition or a clear result from the election, like many people are around the world,” he said earlier this month. “If it is less clear, there may be some disruptions and we need to be ready for any outcomes, and I think that’s what Canadians would expect of their government, and we’re certainly reflecting on that.”

Hundreds of billions of dollars cross the border each year in trade networks that thrive not least because of mutual co-operation and the predictability of the bilateral relationship.

Any disruption could prove catastrophic to Canada.

“I’ve made no bones about saying that the greatest damage to the US-Canada relationship is Donald Trump,” said Bruce Heyman, former US ambassador to Canada. “[Trump] has never admitted failure. So when you get down to an election where you either win or lose, he has a hard time accepting the fact that he can lose. He has never used the words ‘defeat’ or ‘loss’ in terms of the election.”

In office, Trump has frequently challenged the norms of the relationship with his country’s closest ally.

He has feuded with Trudeau, calling the prime minister “two-faced”. He has slapped tariffs on aluminium and steel and forced a redrafting of the continent’s free trade agreement. He has called into question Canada’s critical alliances such as Nato, and the missile defence system Norad.

Trump’s administration has also failed to stand up for Canada during diplomatic rows with China, Russia and Saudi Arabia, leaving the country to fend for itself.

“And I think a second term of Donald Trump will be an extreme version of what we have seen in the first,” said Heyman.

While the Trump era may mark a historic low in the relationship, he is not the first US president to oversee strained relations with Canada.

Prime ministers and presidents have often sparred in past, most recently when Canada decided not to join the US in its invasion of Iraq.

Trudeau’s father, Pierre Trudeau, who was prime minister for 15 years from the 1960s to the 1980s, likened the relationship to that of a mouse beside a snoring elephant. His clash with President Richard Nixon led to a period of chilled relations.

“It is time for us to recognise … that we have very separate identities; that we have significant differences; and that nobody’s interests are furthered when these realities are obscured,” Nixon told the Canadian parliament in 1972.

But the current damage is clear: a recent poll found that Canadian sentiment towards the US had reached its lowest point in 40 years. Only 29% of residents have a favourable view of their southern neighbour.

And many blame Trump: nearly 66% want Joe Biden to win the election.

But whatever happens on 3 November, tussles over trade and tariffs are likely to persist. A Biden administration would still face domestic pressure to bring manufacturing jobs home and to maintain hardline US positions on commodities such as softwood lumber.

“Because Trump is so unpopular in Canada, people naturally tend to idealise what a Biden presidency would look like,” said Juneau. “But the idea Biden would just erase all of the bilateral trade irritants between the two countries is not true. And I think the Canadian government understands that very well.”