US President Donald Trump has said his tariffs on Canadian goods are necessary to force action on the migrants and drugs entering the United States through its northern border. He has also described billions of dollars in daily cross-border trade as a US subsidy and claimed Canada would not be "viable as a country" without it.

Trump, however, is granting a one-month exemption on his stiff new tariffs on imports from Mexico and Canada for U.S. automakers, as worries persist that the newly launched trade