By Louise Blais

September 10, 2026

As I read Senator Peter Boehm’s account in Policy magazine of being at the Canadian Embassy in Washington on September 11, 2001, vivid memories of that morning came rushing back.

As Cultural Attaché at the embassy, I had a television, so staff gathered in my office and together saw the second plane hit the World Trade Center in real time. One colleague had a sibling who worked in one of the towers. We gasped and held his hand.

We knew immediately that the United States was under attack.

Minutes later, from the embassy windows, we saw smoke billowing from the Pentagon. Then came the sonic booms. Fighter jets flew harrowingly low over Washington — made more disconcerting because airspace over downtown D.C. was normally restricted.

Reports suggested that more hijacked aircraft might be heading toward the capital. We had no idea what would happen next.

For many of us, the fear was intensely personal. Our children were in daycares and schools across Washington, some near landmarks such as the Capitol, that suddenly seemed like possible targets.

The embassy’s senior staff were meeting behind closed doors, (ironically, in retrospect) on softwood lumber, with Ambassador Michael Kergin. I raced upstairs to the executive suite, where the Ambassador’s assistants were gathered in front of a television in stunned silence.

“Has anyone told the Ambassador what is happening?” I asked.

They hadn’t. They did not want to interrupt the meeting.

I walked to the boardroom door and opened it without knocking. Every head turned, no doubt wondering what the Cultural Attaché was doing bursting into the Ambassador’s senior staff meeting.

“America is under attack,” I said. “The Pentagon has been hit. There are reports of more planes heading for Washington. What are your instructions, sir?”

That morning, none of us knew what the next few hours would bring. But one thing was clear: it never occurred to us that this was simply someone else’s crisis.

What strikes me, 25 years later, is how instinctive that reaction was.

Within hours, Canada opened its airports to hundreds of diverted aircraft and tens of thousands of stranded passengers. In Gander, Newfoundland, Canadians opened their schools, community centres and homes to complete strangers. Within weeks, Canadian forces deployed alongside Americans and other allies in Afghanistan. NATO invoked Article 5 for the first time in its history: an attack against one would be considered an attack against all.

But the Canadian response went deeper than alliance obligations. September 11th exposed what geography had already determined: the security of Canada and the United States could not easily be separated.

In the years that followed, we acted accordingly. We strengthened border security and intelligence cooperation while trying to preserve the movement of people and goods on which both economies depended. We deepened cooperation in defence and law enforcement. NORAD evolved. Our militaries operated together abroad and guarded the continent together at home.

There was friction, of course. There always is between sovereign countries, particularly when one is a superpower and the other lives beside it. Canada did not follow the United States into Iraq. We disagreed over softwood lumber, agriculture, pipelines and much else. Yet beneath those disputes remained a durable assumption: whatever divided us, there was more that united us, and both countries benefited from working together.

That assumption deserves another look today.

The relationship between Canada and the United States has entered one of its most difficult periods in generations. Tariffs have been imposed and answered with counter-tariffs. Governments are reconsidering procurement relationships, while companies reassess supply chains built over decades. Economic dependencies once celebrated as evidence of successful integration are increasingly described as vulnerabilities. Political rhetoric on both sides has hardened.

I will never forget standing in the Canadian Embassy, watching smoke rise from the Pentagon and hearing fighter jets overhead. We did not know what would happen next. But did know something fundamental: the security of our neighbour was inseparable from our own.

It is tempting to view this principally as a trade dispute. That understates what is happening.

For much of the postwar period, Canada and the United States progressively built a continental economic and security space. Geography gave us extraordinary advantages: abundant energy and natural resources, immense agricultural capacity, advanced industries, deep capital markets, technological leadership, integrated infrastructure and access to three oceans. Mexico’s growing industrial capacity added another dimension.

As the world fragments into competing economic and strategic blocs, those assets should be becoming more valuable. Instead, we are making it more expensive to trade with one another.

This is where the memory of September 11th becomes more than an anniversary for me. Imagine if one of our countries were attacked tomorrow?

Would Canadians instinctively regard an attack on the United States as a threat to our own security, as we did 25 years ago? Would Americans instinctively see a serious threat to Canada in the same way?

I believe the underlying answer remains yes. Our geography has not changed. Our defence systems remain deeply intertwined. Our intelligence agencies cooperate. Our economies remain extraordinarily connected. Millions of families, businesses and communities live that relationship every day.

But something important has changed: we now feel the need to ask the question.

That should concern people on both sides of the border.

It raises another uncomfortable question: Can two countries credibly plan to defend a continent together while deliberately inflicting economic pain on one another?

Canada and the United States are investing heavily in continental defence while placing new barriers between the same economies that support it. These decisions accumulate. A tariff can be removed. A regulation can be rewritten. A trade agreement can be renegotiated. Industrial capacity that moves elsewhere is much harder to bring back.

So is trust.

This does not mean Canada should accept every American demand in the name of continental harmony. Sovereign countries have interests, and Canada must defend its own. The United States will do the same. There will be serious disagreements over trade, defence spending, China, the Arctic and our respective economic relationships with the rest of the world.

The challenge of diplomacy is to manage those differences without allowing them to consume the larger relationship.

The objective should be larger than preserving yesterday’s trade agreement. It should be preserving North America’s capacity to act as a continent.

Canada, the United States, and Mexico possess an extraordinary combination of advantages: energy, agriculture, critical minerals, advanced manufacturing, technology, capital and a market of nearly 500 million people. Our geography protects us in ways that countries elsewhere can only envy. Our economies have spent decades learning how to produce together.

At a moment when economic power is increasingly an instrument of national power, dismantling that advantage would be a peculiar form of self-harm.

And that brings me back to Washington on September 11, 2001.

I will never forget standing in the Canadian Embassy, watching smoke rise from the Pentagon and hearing fighter jets overhead. We did not know what would happen next. But we did know something fundamental: the security of our neighbour was inseparable from our own. “They” were not under attack, we were. It was a morning for instinct, and our instinct was not to run away, it was to help.

The Canada-U.S. relationship does not require nostalgia. It requires perspective. Governments will change. Presidents and prime ministers will come and go. Trade disputes will be settled or replaced by new ones. Geography will remain.

It took generations of Canadians, Americans and, increasingly, Mexicans to build a continental advantage that much of the world would gladly possess.

The question before us is whether we still recognize its value. On that terrible September morning 25 years ago, we did.

Policy contributing writer Louise Blais served as Canada’s ambassador to the United Nations and as consul general in Atlanta. She is now diplomat in residence at l’Université Laval.