UK used to have that kind of protection up until a few years ago, but they decided it was not worth it.

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"?