“Trade wars are good,” tweeted U.S. President Donald Trump, “and easy to win.”

And just like that, we’re back in the thick of it: Trump, looking to Make America Great Again, has threatened to use section 232 of the Trade Expansion Act of 1962 to impose tariffs of 25 per cent on steel imports and 10 per cent on aluminum, suggesting it’s a matter of U.S. national security. That would have a heavy impact on Canada, as it is the number-one supplier of both steel and aluminum to the United States. Of course, those proposed levies may just be more bluster for the ongoing NAFTA negotiations; indeed, Trump has said that a “new and fair” NAFTA deal would prompt the U.S. to consider an exemption.

But several things indicate things could be serious, including the Dow’s initial slump in reaction and many Republicans’ frenzied opposition to the decision. More worrying, even, is the fact that it’s entirely consistent with the rhetoric Trump campaigned on—namely, getting blue-collar workers in distressed industries back on the job with protectionist measures.

This was excerpted from the 7 March 2018 edition of Maclean's.