Should we be arming ourselves against the USA?

It's crazy to think that Canadians are seriously talking about beefing up out national security as defence against, not China or Russia, but our erstwhile ally, the USA. But that is where we find ourselves. 

Here's the scenario: the USA gradually frames Canada as an enemy by tying it to various political and territorial grievances, and questioning its legitimacy as a sovereign nation (that part is already happening, albeit largely based on lies); the USA gradually expands its rhetoric, painting Canada as an outright security threat, if only because we could at any moment restrict access to critical resources that the USA needs, like energy, potash, water, etc; with this pretext, the US would then end intelligence and miltary cooperation (e.g. NORAD, Five Eyes, etc); demands for territorial concessions, maybe starting with an adjustment to the border of the Great Lakes, would be backed by the explicit threat of military force; at which point a full-scale military invasion is not beyond the realms of possibility.

This scenario is perhaps not a likely one - 10% probability? 5%? 1%? - but as the article points out, its probability is not zero. We would then be very much in a Ukraine situation, and we know how that turned out. It therefore behooves us to prepare ourselves militarily for such an eventuality, so the argument goes. There are even those, in all seriousness, calling for a Canadian nuclear weapons program as a deterrent.

It's easy to pretend that such an eventuality is beyond all sober prospect. It's easy to assume that cooler, less unhinged heads will prevail, that the US courts or military will quash such a scenario before it comes close to reality, or that the American people themelves will rise up in the face of such an enormity. 

But, if that non-zero probability exists, can we afford to ignore it?