They wouldn't have to. The US isn't going to start shelling and launching cruise missiles against our infrastructure, they would send an occupying force across the boarder by road. "We're just here to free those Albertans who are being held against their will."

No Canadian is gonna roll over and let US troops walk down their street, there are scores of people ready to block roads or burn down a building rather than hand it over. And there are the hundreds preppers hoarding guns in their basements, ready to take a shot and then fuckoff into a crowd of people willing to hide them.

The US could take Canada but it would be such a blatant and open act of unprovoked aggression I would be willing to bet even China would put pressure on the US to top, if only to protect their assets in Canada.