When new technology or new economic innovations first emerge, smart people often sense where they might lead—even though their most profound consequences might be decades away. Karl Marx wrote large volumes about the consequences of capitalism—volumes that in many ways are still being vindicated—when capitalism and industrialization were only just getting off the ground. Tocqueville did something similar in the 1830s about democracy, which at that time only really existed in the United States.

In the same way, the advent of television, in the 1950s and 1960s troubled a great many people who thought it would tend to debase public life. In 1958, Edward R. Murrow, the great newsman, warned that television threatened the nation’s survival because it was using its power to distract the citizenry from painful realities. And more than 40 years ago my father, a civil servant and diplomat, who was then about 60, made a related remark. “One of the things we feared about television,” he said, “was that it would produce a great demagogue. But apparently, such men lose their appeal when you see them up close.”

Both of those fears seemed to be exaggerated at the time, because the customs and restraints that kept civilization and the American political system in place were still effective. Now however, decades later, the early warnings about the medium seem to be bearing fruit. The world of television has indeed taken over American political life, increasingly replacing political parties and local politics as the road to political power.

During its first two dominant decades in American life, the 1950s and 1960s, television functioned within the consensus culture that had grown out of the era of the Second World War. Its situation comedies gave us typical families with which to identify, the laugh tracks taught us what was funny, and its news organizations gave us the facts in calm, stentorian tones, rarely questioning what the nation’s political leadership was telling the people. No demagogue could use raw emotion to win the support of a whole major political party in those days because the people trusted the government.

Fissures caused by the civil rights movement and the Vietnam War, sadly, broke up that postwar consensus, and in the presidential election of 1968 a regionally based demagogue, George Wallace, managed to carry five states and 13.5% of the popular vote. The major parties managed to re-absorb his votes during the next three elections, but meanwhile, television was demonstrating an ability to elevate its own stars above any political figures. Walter Cronkite reigned for many years as the most trusted man in America, while numerous sitcom stars occupied a far larger place in the American imagination than any U.S. governor or Senator. ...