Finally, the need for tougher antitrust enforcement is dawning on politicians across the American political spectrum. One company dominates online retail. Two ride-hailing companies dictate wages for hundreds of thousands of drivers. In agriculture, two chemical companies control the market for the most important seeds and have the leverage to gouge farmers. This is why a number of Democratic presidential contenders, including Bernie Sanders on the left and Amy Klobuchar in the center, have vowed to act against concentrated corporate power. Meanwhile, Donald Trump’s Department of Justice has initiated investigations of big tech companies. If federal agencies start busting up monopolies, halting big corporate mergers, and stopping predatory practices, the two of us would enthusiastically welcome the government’s new vigor.

But government agencies like the Justice Department and the Federal Trade Commission shouldn’t be the only check on corporate power. The other, equally vital way to keep monopolies and near-monopolies in check is to build up the power of everyone else in the economy—the workers and small-business owners who, in making their livelihoods, must interact with ever-larger corporate giants. Especially when regulators stand down, ordinary people have to be able to join forces and create unions and cooperatives that could hold the largest corporations in check. But all too often, American laws—including, ironically, antitrust laws—put up barriers to this kind of collective power.

You might think of antitrust law, which led to the breakup of Standard Oil and AT&T, as applying primarily to giant corporations. Yet the same set of laws also prevents some of the weakest players in the economy from finding their strength. A corporate cartel whose members set artificially high prices for goods is illegal under long-standing antitrust rules, but so are groups of powerless independent contractors—Uber drivers, home health-care providers, and millions of other workers—or small firms banding together to compete on fairer terms. Indeed, while antitrust enforcers have done little or nothing to check the power of corporate monopolies and stop consolidation, they have attacked the collective action of workers and small firms as illegal collusion. Promoting a rebalancing of power in the economy will require not just more antitrust enforcement against big corporations but a reorientation of antitrust.  […]