Canada and the EU already have a trade agreement since 2016. The UK economy is about 1/5th that of the EU, not enough to move the dial, and they kind of went off in the opposite direction around that same time...

You'd need n^2 "NATO"'s then, because EU has implemented many really shitty policies too and someone would want to fight back against that too. UK may do the same.

And we already have an actual NATO example, where one member attacks countries around the world, one of those countries fights back, threathening to attack american bases even in europe if needed... and now other nato members might get involved in a war that was started by one of it's own members, that no one else really wanted, and side on the side of the agressor ( https://www.aa.com.tr/en/europe/nato-chief-reaffirms-allianc... ). To turn back into economics, what happens when EU declares an "economic war" against china, china retalites (by eg. banning exports of something we really need)... does canada go along and threathen it's own economy? Or do they form a new "NATO" with "everyone-else except EU"?

That will continue with only cars made in Canada not having Canadian tariffs. You make 100,000 cars in Canada everything above that amount is subject to tariffs.

Autos are more obvious than the dairy industry, even though Trump claimed a couple of days ago that the reason there was an imminent deal is because Canada allegedly agreed to eliminate dairy tariffs? Trade negotiations have stalled almost certainly because Canada isn't actually willing to give up dairy tariffs.

No deal is better than a bad deal.

>The Carney administration is on much firmer political ground

I don't think so. Time really isn't on Carney's side either.

Carney's new tariffs fall on those who, in aggregate, did not vote for him. The average Carney voter has been very vocal about wanting to pursue this tactic- that's why they elected him. (That average voter is an Eastern retiree whose holdings are generally in real estate, so they don't care about any other economic sector beyond that which keeps their property values high, especially compared to the feel-good Elbows Up stuff.)

But Carney's currently having trouble just keeping the country together at this point. That's why he's approving projects he really doesn't want to approve out West, like those oil pipelines, because the West has credibly signaled that that they might just ban Carney and his Eastern voting block from making law and collecting tax from them if development of their part of the country is hindered any further. But if it's not hindered, they'll grow in political power, which is also an inherent threat to Ottawa's power (just not immediately).

And yet here Carney is- for the second time now- imposing more economic roadblocks that drive up consumer prices and put more people out of work for no reason other than his voting block wanting it that way. "Just retaliate" might be the least bad option for Carney to pander to that voting block, but every concession to them drives the country closer to separation, and that has time pressure too.

There is no grand vision. Trump has an irrational love of tariffs. He just likes them, they feel right to him. It is entirely that we have a presidential system with an executive that is capable of too much unilateral action, and we elected someone to that office who is unfit for it.

  > The thing that I really struggle to understand is what the grand vision behind this is.

This is something so far removed from the way normal, constructive way people (have to) think and behave with each other as a prereq to participate in society that they will inevitably fail to see this parasitical dynamic, because there is no way they can relate to that from their own frames. Even when we learn about this we will instinctively dismiss it. It doesn't fit our frame of reference, so we decide this can't be true.