Contrary to the conventional view of an American economy bubbling with innovative small companies, the reality is quite different. The rate at which new businesses have formed in the United States has slowed markedly since the late 1970s. Big Tech’s sweeping patents, standard platforms, fleets of lawyers to litigate against potential rivals and armies of lobbyists have created formidable barriers to new entrants.

The patent system is crucial to innovation. The law gives 20 years of patent protection to inventions that are “new and useful,” as decided by the Patent and Trademark Office. But the winners are big enough to game the system. They make small improvements warranting new patents, effectively making their intellectual property semipermanent. They also lay claim to whole terrains of potential innovation including ideas barely on drawing boards and flood the system with so many applications that lone inventors have to wait years. The White House intellectual property adviser Colleen V. Chien noted in 2012 that Google and Apple were spending more money acquiring patents (not to mention litigating them) than on doing research and development.

Antitrust laws used to fight this sort of market power. In the 1990s, the federal government accused Microsoft of illegally bundling its popular Windows operating system with its Internet Explorer browser to create an industry standard that stifled competition. Microsoft settled the case by agreeing to share its programming interfaces with other companies. But since then Big Tech has been almost immune to serious antitrust scrutiny, even though the largest tech companies have more market power than ever. Maybe that’s because they’ve accumulated so much political power.

In 2012, the staff of the Federal Trade Commission’s Bureau of Competition submitted to the commissioners a 160-page analysis of Google’s dominance in the search and related advertising markets, and recommended suing Google for conduct that “has resulted — and will result — in real harm to consumers and to innovation.” But the commissioners chose not to pursue a case. Investigators also found evidence that Google was pushing its products ahead of competitors’ on search results, though no legal action was recommended on this point.

It’s unusual for commissioners not to accept staff recommendations, and they didn’t give a full explanation. The F.T.C. noted a competing internal report that recommended against legal action, but another plausible reason has to do with Google’s political clout. Google is now among the largest corporate lobbyists in the United States. Around the time of the investigation the company poured money into influencing both the commissioners and the commission’s congressional overseers.

GOOGLE is heading into a major fight with antitrust officials in the European Union for some of the same reasons the F.T.C. staff went after it. Not incidentally, Europe is also investigating Amazon for allegedly stifling competition in e-books, and Apple for doing the same in music. While many on this side of the Atlantic believe Europe is taking on these tech giants because they’re American, another possible explanation is that Google, Amazon and Apple lack as much political clout in Europe as they have here.

Economic and political power can’t be separated because dominant corporations gain political influence over how markets are maintained and enforced, which enlarges their economic power further. One of the original goals of antitrust law was to prevent this.