Canada must consider even unlikely threats — including an American invasion

Prime Minister Mark Carney says he has considered the possibility of American military action against Canada, and that the Canadian Armed Forces had examined potential responses.

Such a scenario remains extraordinarily unlikely, but that’s precisely why it belongs in contingency planning. Serious governments do not dismiss low-probability, high-consequence risks simply because they appear remote.

The first responsibility of the prime minister of Canada, as head of government, is to protect Canadians. That responsibility requires preparing not only for the most likely threats, but also for the unlikely scenarios that could have profound consequences for the country.

In intelligence and security circles, these possibilities are sometimes described using a “swan” metaphor. Preparing for likely events, or “white swans,” is routine.

Equally important, however, is considering “black swan” events: highly improbable developments that fall outside normal expectations but could have disruptive and far-reaching effects.

Why plan for black swan events?

First, contingency planning often yields benefits beyond the specific scenario being examined. By challenging assumptions and exploring unconventional possibilities, organizations can identify vulnerabilities, uncover strengths and develop habits of adaptive thinking. The value lies not only in the plan itself but in the planning process.

A future threat to Canada may have little resemblance to a hypothetical attack by the United States, yet the lessons learned from examining an unexpected attack could inform responses to other contingencies, including missile, cyber or hybrid threats that exploit North America’s geography.

Second, Canada has a long history of planning for unlikely but consequential scenarios. During the period between the First and Second World Wars, Canadian military planners developed Defence Scheme No. 1, which considered the possibility of conflict with the U.S.

American planners, for their part, developed War Plan Red — a scheme to invade Canada in the event of a war with the United Kingdom.

Neither expected war, but both recognized the importance of understanding strategic options. During the Second World War, the United States-Canada Basic Defence Plan (referenced as the Black Plan) was penned by Canada to respond to a scenario should Germany defeat the U.K., leaving Canada and the U.S. vulnerable to the Axis powers.

Consequences of failing to prepare

Canada also has experience failing to plan. The Fenian raids committed by the Fenian Brotherhood (an Irish American organization determined to force the U.K. to withdraw from Ireland) conducted armed incursions into Canada, targeting military fortifications in 1866, 1870 and 1871. The Canadian militia were poorly prepared for such attacks.

The 9/11 attacks were also an example of a black swan event because their scale and impact were largely unexpected, even though there were warnings of a potential terrorist threat. They fundamentally changed how Canada thinks about security and how the North American Aerospace Defence Command views air threats. The attacks generated new homeland security institutions on both sides of the border.

Third, preparing for a contingency does not make it more likely. Failure to consider its consequences, however, can leave governments scrambling in a crisis. Scholars such as political science professor Aisha Ahmad have argued that Canada should think more seriously about its vulnerabilities and resilience in an increasingly uncertain international environment.

Her broader work on conflict and state fragility serves as a reminder that close relationships, deep economic integration and longstanding partnerships should never be mistaken for guarantees against future tensions.

Even families and neighbours can be pitted against each other in devastating civil wars. Strategic planners must assess capabilities and intentions as they exist, while remaining alert to how circumstances can change.

Preparation is rarely wasted

History suggests that political leaders’ statements should not be dismissed outright simply because they appear improbable. Some of U.S. President Donald Trump’s threats, for example, have come to fruition.

While campaign rhetoric, negotiating tactics and public comments don’t always translate into policy, prudent governments evaluate threats based on consequences as well as likelihood. The purpose of contingency planning is not to predict the future, but to ensure decision-makers are not caught unprepared should an unlikely event occur.

Preparation is rarely wasted. Even when the scenario never materializes, the process strengthens institutions, sharpens strategic thinking and improves readiness. The costs of planning are often modest compared to the costs of surprise. Time and again, history has shown that ignoring unlikely risks can prove far more expensive than preparing for them.

Andrea Charron does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.