You probably think of the US-Canada border as the ultimate "good fences make good neighbors" success story. It's the longest undefended border in the world. People cross it for cheap gas, better poutine, or just to say they did. But honestly, the idea of a Canada vs USA war isn't some far-fetched alternate history trope. It was a very real, very terrifying possibility for over a century.
History isn't always a straight line.
Sometimes it's a messy series of "almosts" and "what-ifs." If you look at the archives, you'll find that for a long time, the US and Canada (well, the British colonies that became Canada) were basically two neighbors staring at each other over the fence with their hands on their holsters.
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The War of 1812: When It Actually Happened
Let's get the big one out of the way. The War of 1812 is the only time the US and the territories we now call Canada went to total, "burn-it-all-down" war. Americans often call it the "Second War of Independence," while many Canadians see it as the foundation of their national identity.
Thomas Jefferson famously said that taking Canada would be a "mere matter of marching." He was wrong. Very wrong.
The US had a massive population advantage—about 7.7 million people against Canada's 500,000. It looked like a blowout on paper. But the US military was a disaster at the start. They tried a three-pronged invasion in 1812 and every single one failed. One army surrendered at Detroit without even firing a shot.
Burning the Furniture
In 1813, American troops crossed the lake and torched the town of York (now Toronto). They burned the parliament buildings and messed the place up. A year later, the British got their revenge by sailing into Washington, D.C., and burning the White House.
By the time the Treaty of Ghent was signed in 1814, both sides were exhausted. Nobody really gained any territory. It was essentially a reset button, or what historians call status quo ante bellum. But for Canada, the win was simple: they didn't get conquered.
The Pig War of 1859: A Literal Hog Started This
If the War of 1812 was tragic, the Pig War was just weird. In 1859, on San Juan Island (between Washington State and Vancouver Island), an American farmer named Lyman Cutlar found a pig rooting around in his potato patch. He did what any frustrated gardener would do—he shot it.
The pig belonged to an Irishman working for the British-owned Hudson's Bay Company.
Things escalated at a ridiculous speed. The British threatened to arrest Cutlar. The Americans called in the Army. Suddenly, you had Captain George Pickett (who later became famous for "Pickett's Charge" in the Civil War) dug in with 66 soldiers. The British responded by sending three warships.
At the height of the standoff, 461 Americans with 14 cannons were facing off against five British warships with 70 guns and over 2,000 men. The British Governor of Vancouver Island actually ordered the British Admiral to land his men and attack.
The Admiral, Robert Baynes, refused. He famously said he wasn't going to "involve two great nations in a war over a squabble about a pig." Good call, Robert.
The Fenian Raids: Irish Independence via Ontario?
After the American Civil War, there was a whole new kind of threat. The Fenian Brotherhood—a group of Irish-American Civil War veterans—decided they could free Ireland by kidnapping Canada.
I'm not joking.
The plan was to invade, hold Canadian territory, and then trade it back to Britain in exchange for Irish independence. In 1866, about 800 Fenians crossed the Niagara River. They actually won a skirmish at the Battle of Ridgeway, making it the last time a foreign force won a battle on Canadian soil.
Ultimately, the US government stopped turning a blind eye and started arresting the Fenians to avoid another Canada vs USA war. But the fear they caused was huge. It actually pushed the different Canadian colonies to unite and form the Dominion of Canada in 1867. In a weird way, Irish-American rebels are partially responsible for Canada becoming a country.
War Plan Red and Defence Scheme No. 1
The most shocking part of this history happened in the 20th century. Even as late as the 1930s, the US military had a top-secret plan called War Plan Red.
It wasn't just a "just in case" folder. It was a detailed, multi-stage strategy to invade Canada.
- Target: Halifax. The US wanted to seize the port to stop the British Navy from landing.
- Strategy: Use chemical weapons (suggested by none other than Charles Lindbergh during recon flights).
- Goal: Turn Canada into a series of American states.
The Canadians weren't just sitting around eating maple syrup, either. In 1921, Lieutenant Colonel James "Buster" Sutherland Brown created Defence Scheme No. 1.
Buster was a bit of a character. He used to drive around the US in a Model T, wearing civilian clothes and taking notes on bridge heights and road quality. His plan was a "lightning strike" invasion of the Northern US. Canadian troops were supposed to seize Seattle, Portland, and Minneapolis, then blow up all the bridges and retreat before the bigger US Army could mobilize.
Why We Don't Fight Anymore
So, why did we stop planning to kill each other? World War II changed everything. The threat of Nazi Germany and Imperial Japan forced the two countries to integrate their defenses. By 1940, the Ogdensburg Agreement created the Permanent Joint Board on Defence.
The Cold War sealed the deal. With the threat of Soviet bombers coming over the North Pole, the two nations built NORAD. You can't really plan an invasion of a guy who is currently sitting in the same radar room as you.
Today, the idea of a Canada vs USA war is a punchline for comedians. Our economies are so tangled that if the US invaded Canada, they’d basically be attacking their own supply chain for oil, electricity, and timber. It would be like a person punching their own stomach because they’re hungry.
What This History Teaches Us
History is more fragile than we think. Peace isn't just the absence of war; it's the result of decades of boring meetings, trade deals, and shared goals.
If you want to understand the modern relationship, stop looking at the 49th parallel as a line and start looking at it as a seam. It’s where two very different histories were stitched together.
Takeaways for History Buffs:
- Check the local sites: If you’re ever in Ontario, visit Old Fort Erie or the Ridgeway battlefield. It’s surreal to stand where these things happened.
- Read the source material: You can actually find the declassified documents for War Plan Red online. They are chillingly detailed.
- Respect the "Almosts": Peace survived because of people like Admiral Baynes who refused to shoot over a pig. Individual choices matter.
The "Special Relationship" wasn't inevitable. It was earned.
To get a better sense of how these tensions settled, look into the Treaty of Washington (1871). It’s the boring document that actually solved the lingering anger from the Civil War and the Fenian Raids, setting the stage for the peaceful century that followed.