More than half the country was against the wars in Vietnam or in Iraq (2003), but they still happened. And if the current administration decides they want to invade Canada, Canada will be invaded no matter what the country thinks. Same goes for Mexico. How it ends, it is a completely different story and another administration's problem.
A great deal changed after Vietnam. Iraq was only possible because the country had a general blood lust against Muslims after 9/11, who were easy for a mostly white christian country to "other".
Nothing like that exists for Canada. Proposals to invade Canada aren't taken seriously by the public. Those who pretend to support it are just trying to piss people off with how stupid they can be.
The heartland of this mostly white christian country is currently busy othering their mostly-christian non-white neighbours (Against whom they are weaponizing ICE) and their mostly-christian mostly-white city dwellers (Against whom they are deploying the army).
For anyone who can stand behind that, a bunch of foreigners in another country won't even register as someone to have any empathy towards.
