In the coming year, both countries will need to find a way to cooperate against authoritarian enemies — Russia, China, Iran, and their acolytes. Once Trump is gone, Canadians and Americans may again note our common fate — not only expressed in terms of historical experience and tradition, but in our shared residence on this most blessed of continents. Donald Trump ultimately cannot succeed in reversing such ties, and whoever comes after him will likely see the logic of restoring them to full health.