Why Canada is preparing for a (long shot) US invasion

ByNadine Yousif and Robin Levinson-King, in Toronto.

Key points

• Before the formation of Canada, the US had attempted to invade British North American colonies, taking control of Montreal in 1775 and almost conquering Quebec City.
• After the US captured Nicolás Maduro in Venezuela, a Leger poll suggested that over 30% of Canadians believed that a US invasion was probable, in January.
• In the war of 1812, the Americans invaded what was known then as Upper Canada, Lower Canada and the maritime colonies repeatedly, resulting in a stalemate.
• The two countries additionally conduct joint Arctic defence missions under the North American Aerospace Defence Command (NORAD), and frequently share intelligence.
• Trump's global tariffs and his often-repeated desire to create Canada the 51st state has led Canada to war game an attack by the Americans.

Prime Minister Mark Carney admitted last week that he has prepared for a once-unthinkable scenario – a US invasion.

Noting the risk was low and the likelihood highly improbable, he informed the New York Times he had a responsibility to consider all possibilities as the US-Canada relationship is redefined under the Donald Trump presidency. "That's just risk management, " Carney remarked.

In 2025, the US president remarked it was "highly unlikely" that the US would ever apply force against Canada. Instead he remarked, he would continue to exert economic pressures to obtain political seeks.

"President Trump has done more than anyone to protect the great people of Canada, " the White House informed the BBC in an official note this week.

Military experts who spoke to the BBC additionally think an invasion is a long shot, pointing to the multiple ways the two countries work together on defence. But the matter is clearly weighing on Canadians' minds.

After the US captured Nicolás Maduro in Venezuela, a Leger poll suggested that over 30% of Canadians believed that a US invasion was probable, in January. Why it is unlikely to happen.

For context, a war between Canada and the US would be complicated and almost tough to imagine, stated Lt-Gen Christopher Coates, a former military officer of 34 years with the Royal Canadian Air Force who held various senior positions.

"I was involved in military operations for my whole career, and we never considered the possibility that there would be a military attack coming from US territory, " he informed the BBC.

Coates, who had served on Nato missions, observed that Canada and the US collaborate on numerous aspects of military defence.

They are both members of the north Atlantic defence alliance. It mandates members to defend a fellow member-nation should they be attacked.

Meanwhile, the two countries additionally conduct joint Arctic defence missions under the North American Aerospace Defence Command (NORAD), and frequently share intelligence.

Since of this, Coates stated he believes an attack by the US on Canada would not commence with an armed assault, but rather with more discreet means like cyberwarfare. Not always the best of friends.

After World War II, Canada and the US became natural allies for the latter part of the 20th Century, and have become heavily integrated economically, militarily and culturally.

But it wasn't always this way. In fact, a core tenet of Canada's identity is its resistance of US expansionism in the 18th and 19th Centuries, remarked Tim Foran, a researcher with the Canadian War Museum.

"Fear of the United States is foundational to the political project that is Canada, " he remarked.

Canada was formed as a collection of British North American colonies who remained loyal to the British Crown when the colonies in the modern-day US rebelled.

In the war of 1812, the Americans invaded what was known then as Upper Canada, Lower Canada and the maritime colonies repeatedly, resulting in a stalemate. During that war, British troops famously burned down the White House in retaliation.

According to Foran, at the time, the colonies that afterwards became Canada relied on Great Britain and its Royal Navy for its defence, as well as indigenous peoples who served as generals in major battles.

Canada again contemplated war with the US post-World War I in response to its growing power and influence.

It drafted a plan that was informed by secret trips to border cities created by Canadian army generals. This person would pose as tourists and snap photos of bridges and highways for intelligence. They additionally spoke to local residents to better understand their enemy.

Meanwhile, a war was an unlikely scenario then, remarked Andrew Burtch, a researcher with the Canadian War Museum with expertise on Canada in the 20th Century, but the Canadians still wanted to be prepared.

"That's part of what militaries do, " he remarked. "They envisage all sorts of different scenarios." What a US invasion could look like.

Even if a US invasion is extremely unlikely, Matthew Schmidt, an associate professor of national security at the University of New Haven in Connecticut, remarked the fact that Canadians were preparing was a sign of just how drastically the global order has shifted.

He continued Canadian leaders do have hard questions to ask concerning how closely they want to continue working with the American military – a partnership that gives them valuable information should they want to harm Canada in any way.

"It's really doing harm to relationships with the United States, and there's a certain amount of legitimate fear, " he remarked.

Americans might not take Trump's comments regarding making Canada the 51st state seriously, he stated, but Canadians clearly do – and are prepared to defend themselves if needed. So what would it be like if it happened? The first phase of a war could be quite short.

As noted on by the Globe and Mail newspaper earlier this year, a US attack would see Canada's strategic positions overwhelmed within a week, according to the model applied by the Canadian military.

Its military would rapidly be outnumbered, forcing Canadian forces to resort to guerilla-type warfare to try to suppress their enemy.

Allied nations like France and Britain would be called on to provide backing and defence for Canada, the newspaper noted in January, citing senior administration office-holders.

Notably, the theoretical model is believed to be the first time in a century that Canada planned for an American assault.

In practice, the modelling is on the lighter end of military combat planning, Coates remarked.

He remarked that Canada, unlike its Nato allies, was lagging behind when it came to having a response plan in place in the event of any ground invasion, and that it was now playing catch-up in this era of unpredictable geopolitics.

Part of that, he remarked, was produced evident by a recent call by Canada's defence chief to drastically growth the size of its military, including the addition of as numerous as 300, 000 lightly trained citizen soldiers.

Notably, an invasion of Canada might not be straightforward from the US point of view either.

Even with its outsized military, the US would have a tough time getting buy-in for a fight with Canada, stated Schmidt.

"I think you would have a large number of American officers who would resign if given the order to invade Canada, " he remarked. "They would see it as an illegal and immoral order."

Schmidt remarked Canadian soldiers and American soldiers routinely train together, and share a mutual respect.

In short, why Canada is preparing for a (long shot) US invasion is the central thread here, and readers can expect follow-up reporting as the picture becomes clearer.