I assume you saw the article (Might have been Rush) discussing how China imports Steel to the U.S. through Mexico. With Canada and Mexico dragging their feet on renegotiation MAFTA, Trump did two things, issue the Trade tariff "bomb" and announce his 2020 re-election campaign .
The MAGA train is not stopping - waiting Trump out may prove dis-advantageous to the rest of the world.
Italy elections today - results may prove interesting
“Should restrictions be imposed on Canadian steel and aluminum products, Canada will take responsive measures to defend its trade interests and workers,” Foreign Minister Chrystia Freeland said in a statement, calling any trade restrictions“absolutely unacceptable.”
The key word in that statement from Freeland is “products”. Why? because Canada doesn’t make more than a boutique amount of raw Steel. (Top 40 List) The Canadians, like the Mexicans, import the vast majority of their raw steel from China. Canada then fabricates products from the Chinese steel. This nuanced point is almost always lost on people who discuss trade. This point of origination is also the fatal flaw within NAFTA.
In essence Canada is a brokerage for Chinese manufactured material, and NAFTA is the access trade-door exploited by China for entry into the U.S. market.