In September 2008, as the economy was imploding, John McCain suspended his campaign for the presidency and canceled a guest spot on David Letterman’s late-night TV show. “I’m more than a little disappointed by this behavior,” fumed the comedian, who liked to warn politicians — only half-jokingly — that “the road to the White House runs through me.” Letterman’s anger was widely publicized, and McCain was deeply chastened. He agreed to appear on the show a few weeks later and twice admitted, “I screwed up.” When the comedian responded, “I’m willing to put this behind us,” McCain practically groveled in gratitude, saying “thank you” five times.

The authors of “Politics Is a Joke!” — S. Robert Lichter teaches communications at George Mason University; his collaborators, Jody C. Baumgartner and Jonathan S. Morris, are political scientists at East Carolina University — point out that in this exchange the “balance of power” clearly favored the comedian, not the candidate. And Letterman wasn’t even the most influential comic of 2008. That would be Tina Fey, whose devastating impersonations of McCain’s running mate, Sarah Palin, on “Saturday Night Live” shredded what was left of the candidate’s credibility.

The writing here is often bland and the arguments repetitive. And the book includes a lot of confusing charts from academics who try — and largely fail — to measure the precise impact of humor on political attitudes. But this is a compelling subject. Jokes are no laughing matter. As the authors put it, “Late night humor has . . . become entrenched as a force in American politics.” A Pew survey found that 28 percent of all adults get some political information from these shows, but that number jumped to 39 percent for voters under 30.

Jesters are as old as politics, of course. Cartoonist Thomas Nast skewered the bosses of New York’s Tammany Hall in the late 19th century, and humorists such as Mark Twain and Will Rogers made “poking fun at a Congress . . . a time-honored American Pastime.” One of Twain’s famous lines still seems pretty fresh today: “Suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself.”

What changed the equation was television. It shifted the focus from institutions to individuals. The authors recount an episode from 1967, when Richard Nixon was rebuilding his political reputation by appearing on the “Mike Douglas Show.” “It’s a shame a man has to use gimmicks like this [television] to get elected,” Nixon complained. A young producer named Roger Ailes shot back, “Television is not a gimmick, and if you think it is you’ll lose again.” Nixon was so impressed that he hired Ailes, and a year later the candidate appeared on the popular show “Laugh-In.” He said exactly four words — the show’s signature slogan, “Sock it to me?” — but Nixon established an important precedent by utilizing a comic setting for a serious purpose: connecting with voters. One commentator said that the brief cameo turned Nixon “into a ‘regular fella’ willing to poke fun at himself.”

‘Politics Is a Joke!: How TV Comedians Are Remaking Political Life’ by S. Robert Lichter, Jody C Baumgartner and Jonathan S. Morris (Westview)

The influence of comedy shows flows from two sources. One is the jokes. The authors analyze more than 100,000 of them and conclude that the most memorable jibes play off “an obvious theme or trope” that already exists: George W. Bush is dumb, Al Gore is stiff, John McCain is old, Mitt Romney is rich. Bill Clinton was the “all-time favorite target of late night comedians” because he had two large appetites that were easily lampooned — food and sex. By contrast, Barack Obama has always been an elusive subject. “Raunchy” makes a much richer target than “remote.”

Comics don’t create these stereotypes, but they inflate and amplify them. As Democratic consultant Mandy Grunwald said in 1999, once the late-night comics “are making jokes about you, you have a serious problem.” And technology has only expanded their impact since then. Jokesters now have far more outlets on cable TV and Web-based channels. Their routines are featured on popular portals such as Politico and archived on sites from YouTube to Hulu. And the best lines go viral on social media. My students don’t have to watch Jon Stewart live, they just go to their Facebook pages or Twitter feeds and download the links their friends have posted.

These comics also play a second role: providing a platform (or a couch) for politicians to advance their images and ideas. The late-night scene has become a “mandatory stopover” on the campaign trail, and in 2008 presidential candidates appeared more than 100 times on these shows.

Their aim is the same as Nixon’s in 1968: to appear as “regular fellas” (or the female equivalent), to come across as “an average guy and a good sport.” The authors actually understate the importance of this point when they say that candidates on comedy shows appeal only to a “niche” audience of “politically inattentive” voters “that takes personality more seriously than partisanship and prioritizes likeability over ideology.” My experience covering politics tells me that the audience for politicians on nonpolitical platforms is far from a “niche” group. Many voters value “likeability” above any other quality. That’s why Obama has appeared on so many different TV outlets, including daytime chat fests such as “The View” and “Ellen” and sporting events such as the Super Bowl. All these venues give him a chance to tell stories, to promote his personality, to send the message: “I’m just like you.”

During the last campaign, Romney refused to go on most late-night shows “because he believed he would be stepping into a hostile environment.” Obama occupied every couch he could find. And exit polls showed the president running 10 points ahead of his challenger on the critical question, “Who is more in touch with people like you?”

The road to the White House might not run through the late-night comics. But you can see it clearly from their studios.

Steven V. Roberts , a former New York Times reporter, teaches journalism and politics at George Washington University.


How TV Comedians Are Remaking Political Life

By S. Robert Lichter, Jody C. Baumgartner and Jonathan S. Morris

Westview. 253 pp. Paperback, $32; Kindle edition, $12.99