Antitrust is the body of law and the recurring political fight over how much market power a company may hold and what the state should do when it holds too much. It began in the United States with the Sherman Act of 1890, aimed at the Gilded Age trusts, and now runs through fights over Standard Oil, AT&T, Microsoft, and the largest technology firms. As a policy question, it asks a question that has never been settled: is the danger of a giant company mainly that it raises prices and dulls innovation, or that it concentrates political and economic power in too few hands?
For most of the twentieth century, American courts asked whether a company was too big by asking whether it was too powerful. Then, over the 1970s and 1980s, the question quietly changed. A new generation of judges and scholars argued that size was only a problem if it raised the prices consumers paid. If a giant firm delivered cheap goods, the law should leave it alone. That single shift, from power to price, is why the government broke up Standard Oil in 1911 but let technology firms grow to a scale earlier reformers would have found alarming. Now that shift is itself under attack. A movement that critics call the neo-Brandeisians argues that the price test missed the point all along, and that concentrated power is dangerous even when the goods are cheap or free. The fight is live, and its outcome is not decided.