Your culture gave the world the glory that is Poutine. You can name your candy wrong if you want to. Also, Coffee Crisp is a thing.
Blame Quebec? Hey, I'm not gonna judge you for preferring large format, half flavoured Pez...(much) over a better version of M&Ms. I had no idea Coffee Crisp was ever in question? What you really want though, is a Crispy Crunch.
We have Pez and M&Ms. We don't have Cadbury candy bars. Yep, Coffee Crisp, Crispy Crunch, hell Mr. Big and Aero are all delish. I'm hoping that changes if we cut a deal with the UK who desperately needs trading partners after Brexit. Seems like there's a chance that will go down.
IOW, it was an irrational response to an event that didn't directly involve the major combatants. If the border issue gets raised, it would depend upon not only who closed the border but why, and who was in Number 10. I'm not suggesting that Britain would see the closing as a justification to go to war with the US, but, again, depending upon who closed the border and why, as justification to take some kind of action (say targeted sanctions). I mean, we'll take a hypothetical where the border's closed by either Trump or a Trumper in the White House. (Who's most likely already invaded Mexico by this point.) Everybody on the planet is going to be particularly antsy at this point. I can see the British PM (provided it's not Boris) going to the EU and saying, "Uh, yeah, so about that whole Brexit thingie, and the Americans fucking around with Mexico and Canada. We'd like to send a strong message to them, but our economy is terribly dependent upon them at the moment. Do you think that there's any way we could rejoin the EU without it sounding like we're rejoining the EU? That way we might be able to do something about the lunatic currently pitching our civilization towards destruction?"
this is pathetically simplistic because it's stupid and I'm not going to do detail work (this time) on stupid, but if you ignore state/province boundaries, and assume some large part of Quebec seriously wants to be independent, my guess is that if you had an ideological split rather than a political boundary split and mapped north America you'd get Liberals-East and Liberals-West, each with a lot of population, and Right-Wing Utopia with a lot of acres and not so many people in between. Very roughly like this (and yes I'm being irrationally generous to Atlanta and Denver who, in reality, would share Miami and Austin's fate trapped deep in Trumplandia)
The Lincoln Project just did an interview with a woman who was part of a task force started by the CIA, in 2017, to see what the biggest clues that a country was on the verge of civil war were. Basically, they boiled down to two things: 1.) A government that wasn't functioning well as a democracy. 2.) Political parties that were primarily divided on religious or ethnic grounds (ie you didn't care about anything else a party stood for, so long as it espoused ideas that reflected religious beliefs you hold or if more people of your ethnic group were in that party, regardless of the parties policies). If you haven't noticed, the US has both of those issues. According to her, the US is rapidly heading into a status where a civil war is going to become more and more likely.