We have enough problems with people coming into the country with false pretenses and fake asylum. The last thing we need is trojan horses from a country thats suddenly started threatening to invade us.

we have a housing crisis being inflamed by an immigration crisis. Now that we are being directley threatened, Canada isn't just a refuge for people to use as a safety net to hide in. If they want to come to the country they can apply through the usual process, but there isn't any special relationship anymore. Thats dead.

if things get really bad, and the US devolves into a civil war, (we will be a part of it). then we can talk about taking in people. but for now its just way too much of a risk for very little reward. Unless they're going to bring their businesses and jobs with them, they would be consumers, not contributors. and we can't afford that as the world inches closer to world war than its ever been. especially now that America is not a reliable ally and more importantly, a threat.