Did he say that he'd threaten to annex Canada and Greenland? Not that I recall.

Did he say that he'd start a war with Iran? No, I'm pretty sure he said "No new wars."

Look, he's a loose cannon. Everyone who voted for him should have known that. But no, he's not doing "exactly what he said he would do when he ran". Some of what he's doing is what he said, and some is completely contradictory to what he said.

(Credit where due: I stole the "kangaroo on speed" line from an unpublished short story. Don't remember the author, or I'd give them credit by name.)

Can you give an example of how, in practice, it would work to hold millions of voters accountable for what their elected representative does?

Worth picking not just Trump, but let's say a few other Presidents around the world, including someone you voted for.