When people discuss politics and the media, the topic is usually bias and spin. Radio, TV, and the Internet today are thick with ideological combat, and public opinion about both news and entertainment media is increasingly split along partisan lines.

Politics and the media, however, have a deeper relationship. Since the founding of the United States, government policies have determined what kind of media would develop, under what rules they would operate, and, as a result, how political parties and candidates would compete with each other. In determining the architecture of communications networks, allocating scarce resources such as radio spectrum, and translating constitutional principles into new technological contexts, the federal government has established a crucial part of the framework of American politics.

Beginning in the 1790s, the United States established a postal network that connected its principal cities with its small towns and villages. Congress guaranteed all newspapers postal distribution and afforded them two kinds of subsidies: discount rates to subscribers and a right of free exchange with other newspapers. As a result, American newspapers were not just formally protected from censorship by the First Amendment but also given substantial material aid. The government thereby created the conditions for both a dynamic and decentralized press and a highly competitive electoral politics. Starting with the Jeffersonians in the late 1790s, political parties quickly discovered that creating networks of partisan newspapers was a route to electoral victory. The election of 1800 didn’t just mark the first peaceful transfer of power from one party to another; it also signaled the invention of a new means of democratic political insurgency: newspaper coverage.

Historians date the popular use of radio for voice communication to November 2, 1920, when Westinghouse’s Pittsburgh station KDKA went on the air to broadcast the results of the presidential election. There couldn’t have been a more fitting occasion for the debut of American broadcasting than an election night. Over the following decade, political decisions about the structural arrangements and rules of broadcasting determined what kind of medium radio was going to become.

Under legislation passed in 1927, the Federal Radio Commission (FRC) began awarding licenses to stations—or withholding them. The most basic choices about broadcasting involved the allocation of the spectrum. The FRC could have -divided up the spectrum among large numbers of low- and moderate-powered stations. But instead it emphasized high-powered stations and adopted criteria for awarding -licenses that favored commercial organizations. Within a short time, CBS and NBC dominated the medium.

Informally, even before 1927, American broadcasters began to work out a set of rules for political access to the airwaves that virtually amounted to a system of private regulation of politics. The key element was a distinction between news (to be covered at the expense of the broadcaster) and advertising (to be paid for by the candidate or party). Subsequently, Congress required stations to “afford equal opportunities” to opposing candidates. An important extension of the equal-opportunities principle came in 1949, when the Federal Communications Commission—which had succeeded the FRC in 1934—adopted the “fairness doctrine.” The doctrine required stations to air controversial news and public-affairs programming and to offer reply time to people who disagreed with their views.

Recent decades have seen radical transformations of the media, and many people tend to see those changes as entirely driven by technology. But legal and political decisions have remained central in determining what kind of media develop. In 1987, the FCC discarded the fairness doctrine, and it no longer uses its authority to promote public-affairs programming. The abandonment of the fairness doctrine also released the broadcast media from requirements for balance and opened the way to the targeting of ideological audiences. In a sense, these developments represent a return to the partisan journalism of 19th-century America. Partisanship was muted in the media through the mid-20th century; now it is far more open, sharp, and often belligerent.

The lesson is as old as the Post Office: the framework we create for communication is a framework for politics. America’s early postal system contributed to a highly competitive electoral system. The classic era in broadcasting favored the two major parties at the expense of others but preserved a degree of balance. Now the U.S. media are in the thick of the political batt-le between conservatives and liberals. No wonder the fight for an edge in the media seems so critical to who wins and who loses in American politics.

Paul Starr is professor of sociology at Princeton University and cofounder of the American Prospect.