Trump said Monday on Truth Social that one of his first executive orders would be to hit Mexico and Canada with a blanket 25% tariff. Mexico and Canada are the second and third top suppliers of goods to the U.S., according to the Office of the U.S. Trade Representative. The U.S. imports the most goods from China.

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.

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.