The US is mostly losing to Iran due to logistics helped along by badly underestimating their enemy. Logistics are much simpler should they attack Canada.

That said, I have a hard time assessing how much drones would help here. I don't expect they would do as well against a better supplied military than Russia has, and a lot of our bases and population centers are very close to our border, but America has shown they are also unprepared to deal with drone warfare effectively. They have also shown strong signs that their more effective leaders are either out of power or being forced to follow bad directions from their civilian leaders. After all, they are in the process of dismantling their foreign bases while waging a war halfway around the world, which only complicates the logistical challenges they already have. I expect drones are also very effective in guerilla warfare, not just the brand of asymmetrical warfare Ukraine is fighting.