The Supreme Court agreed and split Standard Oil into 34 firms. (Rockefeller received stock in all of them and became even wealthier.) In the decades following the Standard Oil breakup, antitrust enforcement generally abided by a core principle: When a company grows so powerful that it becomes a gatekeeper, and uses that might to undermine competitors, then the government should intervene. And in the last century, as courts have censured other monopolies, academics and jurists have noticed a pattern: Monopolies and technology often seem intertwined. When a company discovers a technological advantage — like the innovations of Rockefeller’s scientists — it sometimes makes that firm so powerful that it becomes a monopoly almost without trying very hard. Many of the most important antitrust lawsuits in American history — against IBM, Alcoa, Kodak and others — were rooted in claims that one company had made technological discoveries that allowed it to outpace competitors.

For decades, there seemed to be a consensus among policymakers and business leaders (though not always among targeted companies) about how the antitrust laws should be enforced. But around the turn of this century, a number of tech companies emerged that caused some people to question whether the antitrust formula made sense anymore. Firms like Google and Facebook have become increasingly useful as they have grown bigger and bigger — a characteristic known as network effects. What’s more, some have argued that the online world is so fast-moving that no antitrust lawsuit can keep pace. Nowadays even the biggest titan can be defeated by a tiny start-up, as long as the newcomer has better ideas or faster tech. Antitrust laws, digital executives said, aren’t needed anymore.