Canada has war-gamed a US invasion — and Carney says it is just risk management

Canada has spent more than a century treating the United States as its closest ally, its biggest trading partner and its most dependable military partner. Last week, Prime Minister Mark Carney confirmed that his government has nevertheless war-gamed the unthinkable: an American invasion.

Speaking to the New York Times while in New York for the United Nations General Assembly, Carney said he had a responsibility to consider even the most extreme scenarios. He called such planning "just risk management", stressing that the risk was low and the likelihood of an attack highly improbable. "I think you have a responsibility in these roles to look at extreme tail risk," he said. "That's not a base case, but it would be irresponsible not to."

Why Ottawa started planning

!Canadian Prime Minister Mark Carney in a formal portrait Credit: Lea-Kim, CC BY-SA 4.0, via Wikimedia Commons

The roots of the planning lie in a relationship that has frayed badly since Donald Trump's return to the White House. The American president has hit Canada with sweeping global tariffs and repeatedly talked about absorbing the country as America's 51st state, even mocking his predecessor Justin Trudeau as a mere "governor". In 2025, Trump said using military force against Canada was "highly unlikely", adding that he would instead apply "economic force" to get his way.

Ottawa is plainly not taking that as the final word. In January, after the United States captured Venezuelan leader Nicolás Maduro in a dramatic operation, a Leger poll found that more than 30 per cent of Canadians believed a US invasion was likely. The trade war has only sharpened nerves since: earlier this month Canada imposed retaliatory tariffs of between 15 and 50 per cent on more than $20 billion worth of American goods, from steel and aluminium to lumber and dairy, while in August the US had slapped 50 per cent duties on an estimated $28 billion of Canadian exports. VERITY's analysis of the US-Canada trade war sets out how the tariff spiral has reshaped both economies, even as both sides edged toward a possible trade deal.

The White House pushes back

!The South Facade of the White House in Washington, D.C. Credit: Matt H. Wade, CC BY-SA 3.0, via Wikimedia Commons

The White House has dismissed the suggestion that Washington harbours hostile intent. "President Trump has done more than anyone to protect the great people of Canada," it said in a statement to the BBC this week. The administration's official line remains that its pressure on Ottawa is economic, not military, and officials point to decades of alliance cooperation as proof that no invasion is on the table.

Carney's government is not publicly arguing otherwise. Defence Minister David McGuinty said militaries routinely prepare for scenarios that may never happen, and urged Canadians to view the war-gaming in that context. The prime minister himself went out of his way to describe the invasion scenario as a tail risk rather than a forecast.

Why experts call it a long shot

Military specialists who spoke to the BBC were blunt: a war between the two countries is, in their assessment, almost impossible to imagine. Lt-Gen Christopher Coates, a 34-year veteran of the Royal Canadian Air Force who served on NATO missions, put it plainly: "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."

Both countries are members of NATO, whose founding treaty obliges members to treat an attack on one as an attack on all — a point underlined at recent alliance gatherings covered in VERITY's NATO summit reporting. They also share responsibility for defending North American airspace through NORAD, conduct joint missions in the Arctic and routinely exchange intelligence. Any American assault would, the experts note, more likely begin with cyberwarfare than with an armed crossing of the world's longest undefended border.

It has been planned before

There is, in fact, a precedent for precisely this kind of thinking. In the 1920s Canada drew up Defence Scheme No. 1, a plan for a hypothetical war with the United States, informed by generals who made secret trips across the border. Washington answered with its own War Plan Red, which included provisions for invading Canada. Both belonged to a different world and were abandoned generations ago.

The deeper history is one of real conflict followed by two centuries of peace. American forces seized Montreal in 1775, and the War of 1812 saw invasions in both directions before the border settled into what became the longest demilitarised frontier on earth. The current planning is the first of its kind in roughly a century.

What an invasion would actually look like

A modelling exercise by the Globe and Mail, reported by the BBC, concluded that Canada's strategic positions would be overwhelmed within a week of a determined American attack — after which resistance would shift to guerilla warfare, with France and Britain expected to line up as Ottawa's allies. Experts stress that any opening move would more plausibly be a cyber campaign aimed at crippling command and communications than a conventional invasion.

The Canadian military is taking the broader threat picture seriously in any case. The country's defence chief has called for up to 300,000 lightly trained citizen soldiers, a proposal that reflects anxiety about everything from hybrid warfare to Arctic security. Guidance from the Government of Canada on defence readiness underlines how seriously Ottawa is investing in preparedness across the board.

A shifted global order — and what to watch next

The episode says as much about a changing world as about any immediate danger. Matthew Schmidt, an associate professor of national security at the University of New Haven in Connecticut, told the BBC he believed "a large number of American officers would resign if given the order to invade Canada", adding that "they would see it as an illegal and immoral order".

Meanwhile the diplomatic chessboard keeps moving. European Commission President Ursula von der Leyen has proposed making Canada an associate member of the European Union, a suggestion Trump called a potentially "hostile act". More on that initiative can be followed through the European Council. Timothy Foran, a researcher at the Canadian War Museum, captured the national mood: "Fear of the United States is foundational to the political project that is Canada." As Andrew Burtch, his colleague at the museum, observed: "That's part of what militaries do." VERITY's world news section will keep tracking the story as the alliance rebalances.

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