President Donald Trump and his defenders claim that his recent tariffs will usher in “a new Golden Age of American industrialization and prosperity.” As the president put it, “Tariffs are not just about protecting American jobs. They’re about protecting the soul of our country.”

But there are two major flaws in this vision of a prosperous, reindustrialized America. First, US factory jobs only became synonymous with middle-class prosperity because of mass unionization. Being pro-factory is not the same thing as being pro-worker.

And, second, even if these tariffs do ultimately help encourage domestic manufacturing — and that’s a very big if — structural factors like automation put a hard cap on the number of total manufacturing jobs that could return. Strengthening US manufacturing is a worthwhile goal, but factory jobs for all is a mirage. To recreate American prosperity, we need unions for all.