Praising Jon Stewart for virtues other than comedy has become a cliché, as James Fallows noted in his Atlantic blog. At this point it’s hard to dispute that Stewart is not only the functional equivalent of a news anchor, but the most influential anchor in America. Likewise, it’s commonly recognized that jokes are merely a happy byproduct of Stewart’s editorial alchemy. Yet the foundation of the Daily Show, the reason it satisfies so deeply as it entertains, is only partly the thorough research and analytical intelligence it brings to bear on current events. The crucial part of Stewart’s formula is an exacting and sometimes harsh moral judgment.

Stewart is a TV preacher and shame is his drama. He was widely viewed as a harsh political critic of George W. Bush and his administration. More accurately, he was a moral critic of Bush, chastising the White House for hypocrisies more than policies (though Stewart was not amused by torture). His great genius is to wake up each day as a newborn, naïve and trusting, and to convey each night his shock and dismay at how soiled he’s discovered the world to be.

If Stewart’s effort to build a moral majority has a launch date, it is Oct. 15, 2004. That’s when, in the process of promoting his funny book, “America,” he appeared on CNN’s Crossfire with Paul Begala and Tucker Carlson and stubbornly, even obnoxiously, refused to be funny. Stewart’s performance required a steely courage and Obamaesque level of self-belief. But he quickly donned his inquisitor’s robe and commandeered the show, transforming it into an expose of bankrupt talk show conventions. He obliterated a tag team of skilled debaters—on their own show—by avoiding their turf, politics, and sidestepping what they mistakenly thought was his turf, comedy. Instead, he pleaded with the Crossfire hosts to change their sinful ways and “stop, stop, stop, stop hurting America” with their cheesy show. Billy Graham couldn’t have said it with more pathos.

Crossfire, of course, was a tower of babble, premised on serial phoniness. The fraud of the professionally feuding hosts. The fraud of their Washington insider guests trading prepackaged sound and fury. The fraud that the form and content of the program represented something grander, higher, than a swampland minstrel show.

A similar fraud is practiced by CNBC and, in fairness, practiced to a greater or lesser degree by virtually every television talking head at a network other than Comedy Central (where the fraud of TV convention is, after all, the central gag). Stewart’s flaying of Jim Cramer, following his devastating eight-and-a-half minute dismantling of Cramer’s network only days before, was locked down by the Daily Show’s crack research team, which produced video of Cramer recalling his shady maneuvers as a hedge fund manager.

But on the Daily Show, the facts are put in service of Stewart’s moral mission. Stewart never once castigated Cramer for being dumb or naïve or mistaken or unwitting as the financial world imploded. His complaint was that Cramer was immoral. That he knowingly withheld knowledge of Wall Street’s seedy machinations and thereby aided and abetted the crooks. In effect, he accused the entire pom-pom brigade at CNBC of cheering on the thugs as they went about their muggings.

It’s tempting to think of Stewart as a post-modern Murrow or Cronkite, creating an oasis of trust in the half-baked desert of television. But he is less and more than that. At its best, his show has more in common with the dramatic moments of the Watergate or Army-McCarthy hearings than with a newscast. It enlightens less by a stream of information than by a moment of revelation.

To get away with this high-handed act, Stewart employs his “jus’ showbiz” deflector, discounting his very real power and authority and routinely miniaturizing himself (telling Begala and Carlson that his lowly show was preceded by a sock puppet; declaring himself a “snake oil salesman” to Cramer). Unlike the cavalcade of television preachers who came before him, the Bakkers and Swaggarts, Preacher Jon has so far exhibited the strength of character to forego the ego-driven cycle of sin, exposure and disgrace that plagues the televangelist ranks.

If he can continue to expose our hypocrisy without making noticeable contributions of his own, Stewart is poised to become one of the most significant figures in television history. He probably is already. It makes you wonder how, in earlier days and under different circumstances, he might have detoured television’s drive to become the stupid—and stupid-making—medium, a status lamented by everyone from Reinhold Niebuhr and Newton Minnow to Ted Koppel. But in the beginning, there was no Preacher Jon.