Incoming Border Czar Tom Homan weighs in President-elect Trump's tariff threats against Mexico and Canada, the showdown with sanctuary cities and the humanitarian crisis on the border.

The president-elect’s opening salvo in trade and border talks with the United States’ neighbors is casting a harsh light on the North American alliance.

The leaders of Mexico and Canada responded quickly, and in different ways. Justin Trudeau, Canada’s prime minister, jumped on the phone to Mr Trump to chat about the “intense and effective connections” between their countries. His deputy, Chrystia Freeland, released a statement about the importance of border security.