We did fight a war with Canada in 1812. We also fought a war with Mexico in 1848, and came very close to another in 1916, but they were not organized to hold up their end.
Imagine T. Roosevelt as the US president while Wilson was president of the slave owning Confederacy. Each allied to a set of partly compatible European powers. Ouch!
Funny, I thought we fought that war with the British. Canada was part of Britain at that time, or did you forget? Why did we fight that war with the British? It was because they weren't respecting the sovereignty of our citizens. They were pretending that our citizens were THEIR citizens, sort of like pretending our land was still their land, but that may be too much of a complication for you to follow it.
We also fought a war with Mexico in 1848, and came very close to another in 1916, but they were not organized to hold up their end.
Mostly a land grab. Not sure there is any other way to slice it than to say that the U.S. sent troops into Mexico to convince them to let go of their ownership of Texas.
Not a good example to bring up for your position.