It was crucial to Canadians, whose country simply would never have existed had the United States won the war. It was the second US invasion of Canada, the first being the C
…ontinental Army's failed attempt to capture Montreal in 1775. All through the first 12 years of the 1800s, American politicians openly discussed their desire to take Canada (which was not a country, but had been a territory by that name for almost 200 years). And it should have been easy. Those politicians knew that Britain was in the middle of a huge and bloody war with Napoleon's empire, and the US had more than 20 times as many people as Canada. Even Thomas Jefferson called the forcible annexation of Canada "a mere matter of marching". It seems likely that an American victory would eventually produce "Manifest Destiny": occupation of the entire continent, apart from southern Mexico. But Jefferson was very wrong. Ten separate American forces did invade, and, in a series of battles across Upper and Lower Canada, all ten were decisively defeated by Canadians, aboriginals, and a small core of British troops (so few that, during the entire war, there were more British troops based in Bermuda than in Canada.) The British counter-invaded, burned the White House, and occupied large swatches of American territory, but showed absolutely no desire to undo the American revolution. Instead the two sides signed a peace treaty that simply restored the original borders. A few weeks later, since word of the peace travelled slowly, Americans won a victory at New Orleans, and the British followed that with an equally important strategic victory, the capture of Fort Bowyer. Both had zero effect on the outcome of the war. Ironically, that second American attempt at invasion brought two very separate English and French-speaking Canadians together to defend their land, and began the first serious discussions of nationhood, without which it seems likely that the various territories would have fallen into American hands, one by one. It was crucial to the US because the British, having defeated the US invasion with just 5200 men, suddenly had close to a hundred thousand battle-hardened troops available after beating Napoleon, and ready to ship to North America and finish the job....had they wanted their colonies back. But the Brits had barely noticed this distant attack. It was also crucial to the First Nations people whose homeland was soon flooded -- and obliterated -- by American settlers. ( Full Answer )