Donald Trump's increasingly strident approach to relations with Canada is provoking fear about the potential consequences north of the border and questions about just how serious the U.S. president-elect actually is.

The race to be Canada’s next prime minister is still at the starting line and Donald Trump has already cast a shadow over it.

Trump—who has seemingly joked of a U.S.-Canada merger before—said if the two countries merge there would be no tariffs, lower taxes and the U.S. and Canada would be “TOTALLY SECURE” from Russian and Chinese threats.