AskACanadian

Canada would have to face an existential threat, like an act of war or terrorism carried out by the US or Israel, before the society can justify that kind of deep divorce. All of the politicians and gatekeepers, or the establishment, are already aligned with active trade with the US. Under this scenario, Canada's enjoyed a long standing "friendship" with the US over generations. This incumbent network would not disappear without some serious shifts in the world.

Canada and the US have similar arrangements of hard and soft political power with Israel. We have networked ties with organizations/clubs, funding, information sharing, diplomatic missions, military contracts, commercial business, and large communities. Both Canada and the US also have an unknown number of Israeli soldiers who reside in each. Almost surely, these networked ties will engage soft power to resist the new scenario or create some kind of stalemate.

Under the new scenario of boycotts and sanctions, I'd hazard a guess that either the US has catastrophically collapsed and has become hostile or there's been some kind of societal change within Canada (state or domestic terrorism or foreign interference) that involves varying degrees of systematic violence to enforce a new power structure. If we followed these two guesses, then Canada would already be in the midst of a recession or depression, and escalated military readiness.

We would perceive a life threatening force in our neighbour...this would not be a good time.

Now if we just flipped a switch and said "oh today we boycott the US", sure I suppose that would just be a depression and further discussions would be needed for concessions.