Jill Lepore investigates how the business of politics got its start:

Political consulting is often thought of as an offshoot of the advertising industry, but closer to the truth is that the advertising industry began as a form of political consulting. As the political scientist Stanley Kelley once explained, when modern advertising began, the big clients were just as interested in advancing a political agenda as a commercial one. Monopolies like Standard Oil and DuPont looked bad: they looked greedy and ruthless and, in the case of DuPont, which made munitions, sinister. They therefore hired advertising firms to sell the public on the idea of the large corporation, and, not incidentally, to advance pro-business legislation. It’s this kind of thing that [Upton] Sinclair was talking about when he said that American history was a battle between business and democracy, and, "So far," he wrote, "Big Business has won every skirmish."