Canada

The US will not invade Canada. At some point, it would require political integration. It would be a generation after that before the Republicans won an election.

There are 40 million people in Canada and more land area than the entire US. At least 75% of Canadians would vote Democrat and that is before the bitterness of an invasion. Even as a single state Canada would swing the House and every President. As multiple states, Canada would swing the Senate. Think of the Supreme Court that would be appointed. The GOP would be completely locked out.

Just allowing Canadians already in the US to vote would have cost the Republicans every presidential race since Reagan.

For the above reasons alone, somebody will stop Trump from pulling the trigger. The US will not invade Canada. Even if they did, they would give it back.

That said, Trump may wage an unbelievably destructive trade war. And the end game for that may be for Canada to submit to total subservience to the US.

We are in a negotiation. The threat of war is just part of that. We hold some decent cards. By appeasing Trump, we start to lose cards. We can get more cards by aligning with the rest of the world both economically, militarily, and socially as fast as possible. The good news is, the world seems to be there for it.