As someone who lives in Canada, I'm hoping we'll be hard to invade the same way Russia is hard to invade. As in, all these US troops who train in Texas and Florida probably won't be conditioned to handle doing stuff when it's -40C outside, so we can all just head north and hope they get stuck and give up lol.

Also, and Americans don't seem to like it when I say this so apologies in advance, but the US is historically not great at winning wars IMO. They're great at starting them, but it almost always seems to end up in a quagmire that just drags on for ages and then gets abandoned. So that's pretty much how I imagine this would go too.