TORONTO — Roughly $900 billion in annual trade between Canada and the United States — and with it, traditionally chummy bilateral ties — is on the brink of upheaval, with President Donald Trump threatening to impose sweeping tariffs on Canada as early as this weekend.

His efforts to “repel the disastrous invasion of our country” by migrants and drugs from Mexico and Canada may soon include stemming the passage of cars. A promise to impose sweeping tariffs on “day one”,