If they enact a tariff like Trump is proposing we're going to have to pivot hard. I've been in favor of Canada trying to join the shengen economic zone for a while - this may be a good opportunity.
I'd support Canada joining the EU for the single and extremely selfish reason that I would love to instantly move to a different EU country. NATO isn't north american, EU doesn't have to be European!
Alas, NATO stands for North Atlantic Treaty Organization - the A doesn't mean American. That's why Canada and the UK are members but Australia and New Zealand aren't.
Still, maybe Canada will luck out and that Europe thing will turn out to not actually be a requirement for joining Schengen or to join the EFTA. One can dream.