Europe is in the same situation, having depended on America for core systems like modern jets and CIC. The only thing they have going is it would be much more difficult to occupy them beyond what their leaders already agree to.

If yall did start economicly decoupling, buying Chinese hardware, and training everyone to wage an asymetric war a la Finland, the calculus for the people who want Canada to remain a US vassal shifts to "OK, we can accept a hostile state on our border, or we can have a 3 day special operation and drive right to Kiev~~~~TorontoOttawa and be welcomed as liberators. And the longer we wait, the more difficult option 2 will be."

While helping dismantle the evil empire is unambiguously good for humanity, I genuinely don't think you have a better option than accept whatever yall are subject to.

That would also crush EUs economy, and hurt all the wealthy/politicians. Many citizens would get angry, and probably vote the status quo out of power.

I agree that it still should be done, because the alternative would likely be worse. But, I think it's unlikely to happen because the people who benefit the most from the way things are won't willingly let it.

Complete and total cessation of trade with the US is extremely unlikely. Countries that have done worse still regularly engage in trade. Even if all of Europe stopped buying and selling with the US, Europe is 500 million people on a planet with 7 billion.

No, it still wouldn't be good for anybody and Trump and his supporters are deluded dingbats but it wouldn't isolate the US.