I guess I had heard about that latest aluminum tariff thing, but didn't it come up a few months earlier too? I've lost track and assumed it was only a tweet, that nothing actually ever happened, as per usual with Trump's pronouncements.
The more I think about it, I now remember wondering at the time what had brought it on, because there was no dispute about anything that I could recall. And why aluminum, did some buddy of his ask for tariff protection for his company? You know, the way capitalists compete for the good of the consumer.
Canadian aluminum is cheaper than American aluminum. Whoever watches the aluminum markets noticed that imports of Canadian aluminum into the United States were increasing. Since American aluminum producers are unable to compete on price, Wilbur Ross over at the Commerce Department (he is the guy that sleeps through meetings) and Larry Kudlow, Trump's economic advisor (and former TV show host) thought a tariff would be a good idea. Trump loves to impose tariffs so it was an easy sell. It is protectionism 101. Even the Wall Street Journal, which is usually pro-Trump said this was a bad idea.
Of course, the result is that Canada is imposing retaliatory tariffs. Canada, like China, is sentient, and therefore knows that retaliatory tariffs should be targeted to products sold by businesses in swing states, so exports by those businesses go down, people lose their jobs, and they all blame Trump. You can see how this could spiral out of control.
https://www.cbc.ca/news/politics/freeland-aluminum-imports-tariffs-trump-1.5677757