"The world has moved on."
Americans certainly have but Canadians - not so much. All one needs to do is view the daily barrage of multiple Trump articles in the GM for proof.
"It is time to let American garbage stew in its own rot."
That comment suggests you've been such a helpful neighbor and now its time to "let" them go their own way. What support are you relinquishing, again?  Refresh my memory.