If there's one thing I learned from Ukraine, it's that a lot of leftists will actually go pick up a rifle and "fight fascism," even if it's 9,000 miles away, over an ocean, they have no idea what they're doing, etc. I even hear of people IRL who tried to finesse a trip to Ukraine.
It's important to note that although their internet arguing skills don't forge them into warriors, a lot of them also don't have the self-preservation instinct to let that stop them from picking up a gun. Indeed, some of them are suicidal and hate themselves. So they're going to kill or make you kill them.
So I expect at least some of the fags making and upvoting anti-Trump webcomics would literally try to kill Americans. I suspect a lot of regular young men would also join up. Another thing Ukraine taught me is that there is a larger mass of somewhat normal 18-25 year olds that are itching for an adventure and can be seduced into war, just like it always was.
Of course this whole post is moot because we'd never invade, and if we did then Canada would crumble in under 2 weeks, if not 2 days, since all of their major population centers are literally on our border and we wouldn't be supplying them with billions of dollars in weapons. But I still find it interesting to talk about because it's important not to underestimate these people. Just because they post gay fanart and live in obese poly households doesn't mean they can't shoot up a school.
I think two things made the Ukraine system unique in that regard.
The first, it was already a war. Someone shot first. Lefties are cowardly and hate to take initiative, its why they always tend to be following some Elite who organizes and fulfills their need for collectivism and hivemind leadership. Ukraine had that covered, with clear black/white sides (to them), so they could just join up with something that already existed and go.
In the US/Canada sense, they would need someone to start the battles before they could overcome this. And maybe some loon might be unfettered in this regard, but not enough to truly feel like they were being a follower.
Which leads into the second part. Russia has this stereotype across Western media of being this broken, poor nation of imbeciles. The Ukraine situation was sold to them as "show up, dab on these evil idiots, GLORY." Most of them didn't really feel like they were going to be in real danger, they'd have superior firepower and tactics, plus RIGHTEOUS MORALITY. They'd play it up for the attention, but you saw many videos of them falling apart the moment the gritty came around.
The US isn't that. We have our stereotypes of being violent, gun toting retards now under the thrall of a fascist with an ego. That's a recipe for actual danger, even if they feel secure in their victory it wouldn't be an absolute slaughter like they expected against Russia. This will preclude everyone except for the demographic you mentioned of young men looking for adventure, but the Foreign Ukraine thing was a lot of older men and women bolstering its numbers. At least in videos, maybe not on the ground.
So I expect the Canadian "response" to be much more petty and pathetic. Like them messing around with people on the border, especially the Washington one where people are used to crossing back/forth regularly. Maybe violence, but more hooliganism than warfare.
The stereotype is correct as the military is comprised of violent gun totting retards.