A common refrain among union critics is that Americans no longer need unions—that unions were well and good for the exploited sweatshop workers of a century ago, but today’s empowered Americans need no such crutch. 

With workers’ incomes falling, and with the United States leading all industrial nations in the percentage of its workers in low-wage jobs, it’s increasingly clear that today’s we need unions for many of the same reasons that the workers of 1912 did: They’re exploited and underpaid. But if it’s only the nation’s most exploited workers who need to band together, why have America’s most talented employees formed unions of their own?

The paradox of unions is that they are at once armies and democracies—an oxymoronic construct that means they can seldom be as efficient as a top-down organization, or as expansively deliberative as, say, an idealized New England town meeting. There no ideal equipoise for a union—some, in which member participation has atrophied, can be essentially autocrat; some are more democratic (although democracy can impede growth if members insist on making the union devote resources to servicing their needs at the expense of organizing new members). The better unions try to balance their dual roles, and that looks like what the Chicago Teachers Union did Sunday night.