What is the point, ultimately, to making a trade deal with someone who threatens every 2-3 days either to "cut off trade" or increase the cost of trade over whatever issue happens to have pissed him off this morning? Talking to the EU? Tariffs. Joined the BRICS? Tariffs. Russian oil purchases? Tariffs. No access to bases? Tariffs. Didn't do X, Y, or Z? Tariffs. And now we have progressed from tariffs to "no more trade." There's just no real credibility to a policy instrument if you either overuse it, use it for anything and everything, or are just all over the place.
Trump threatens to cut off trade with Europe if Canada becomes an associate member of the EU.