Ah I see where you're going with it haha. The only thing would be the repercussions from the rest of the world. Even groups who weren't allied with Canada would use it as an excuse to attack the U.S. As great as your military is, it can't stand up to possibly every country in the world. Even Antarctica would send elite tactical penguins. Plus if somehow you survived and just nuked everyone and were able to contain the fallout or move to the moon, we've slowly been upping the dosage of a lethal biological agent in our coveted maple syrup. If anyone goes too long without having it, they'll begin spouting nonsense about moose, saying abooot, eh and eventually fall over and die in the most horrific fashion, their bodies decomposing into maple leaves in memory of us.