It is a testament to how much Bill Moyers matters that this quiet, humble man can still stir passions. When he announced late last month he would be leaving his award-winning weekly PBS series, “Bill Moyers Journal,” in April, some of us felt as if we were losing a sacred American institution, a repository of the nation’s conscience, while others cheered. Right-wing bloviator Bill O’Reilly went so far as to boast that he had forced Moyers from the air -- a claim that was not only patently false but also a misconception of who Moyers is and what he does. Astonishing as it may be to anyone who has watched Moyers, his right-wing critics seem to see him as just another noisy shill among the army of blowhards, ideologues, demagogues and partisans on the airwaves. They couldn’t be more wrong.

The reason so many of us are already mourning Moyers’ departure is that he is so unlike O’Reilly and that ilk. Though Moyers has certainly addressed the major issues of his times and taken fierce stands on them -- against military adventurism, against violence, against intolerance and hatred, for environmental sensitivity, for real healthcare reform and grass-roots democracy -- and though his recent programs have provided the deepest and most invigorating discussions of these issues on television, most of his work has had little to do directly with politics or policy and nothing at all to do with opinion-mongering. He is far less interested in advancing a particular position than in inspiring moral growth in the hope of creating a more just and beneficent society. In short, far from being another cudgel-wielding pundit, Moyers may be television’s only moralist.

Where Moyers’ critics have gone astray is assuming that Moyers’ journalistic career was a continuation of his political career. Born in Oklahoma and educated in Texas, Moyers served as a teenage summer intern for Sen. Lyndon Johnson, eventually working in Johnson’s campaign and then following him to Washington when Johnson became vice president. After Johnson assumed the presidency, Moyers served as his de facto chief of staff and press secretary. It is a tribute to Moyers that when he came to doubt the wisdom of the Vietnam War -- and even Johnson’s sanity -- he left the White House and entered journalism as the publisher of Newsday, a Long Island paper later bought by this paper’s parent company at the time.

The Washington Moyers was the political Moyers, the Moyers who was once even touted by admirers as a presidential possibility. But though he was in politics, he was never entirely of politics. Though he had earned a degree in journalism from the University of Texas, he had also received a degree in divinity from Southwest Baptist Theological Seminary, and he was later ordained as a minister, which is what he was doing when Johnson recruited him. Still, even in Washington, Moyers never abandoned his ministerial vocation. Rather, he took it into politics, where he assisted Johnson in the formation of the Great Society, and he took it into journalism, at PBS, CBS and NBC, where he became a voice of reason and decency -- all too often a lone voice.

He has his mission

One cannot understand Moyers without understanding his theological training and his moral conviction. His mission has always been to make things better, not louder. In many respects he operates within the religious tradition of the social gospel with its concern for vivifying and actualizing religious values, though he has also called himself a Christian Realist, after the great theologian Reinhold Niebuhr, by which he means, as he put it, to see the “world as it is, without illusions, and to take it on. . . . “

This, far more than politics, explains Moyers’ fervent populism. Populism is where his hardscrabble upbringing, his feeling for his fellow man and his Christianity has led him. (Of course Christianity has also led others to the opposite pole.) For him, politics is a means to a moral end. Christian Realism may also explain his tenacity. Moyers has said that one has a moral obligation to right wrongs, and in this cause, he has been fearless, which is why O’Reilly’s braggadocio is so ridiculous. Moyers has never flinched in a fight. He is girded in moral armor.

But if Moyers has been more interested in morality than in politics, he has also been more interested in the ways one arrives at moral conclusions than in the conclusions themselves, which is another quality that makes his programs so distinctive. For Moyers, real morality isn’t posited; it is arrived at, so that debate itself is a moral process and ideas part of an ongoing moral exploration. No one on television has centralized the discussion of ideas as much as Moyers. His famous 1988 series with the anthropologist Joseph Campbell in which Moyers explored cross-cultural archetypes was also the archetype for many of the programs that followed: among them, “A World of Ideas,” “Sister Wendy in Conversation,” “Faith and Reason” and “Fooling With Words,” in which he interviewed poets. Who else on television would devote a series to poets?

Moyers has always sought the most interesting thinkers, people who would never otherwise be on television, and then discussed their ideas in search of timeless truths. In the last two months alone, he has interviewed naturalist Jane Goodall, playwright Anna Deavere Smith, economist James K. Galbraith and U.N. human rights investigator Richard Goldstone -- a disparate group, none of them exactly headliners. In a sense, then, the title of one of his series, “Now,” was a misnomer. Moyers has never been about now. He has always been about something beyond the moment. Or put another way, while everyone else in the media has been exploring topography, Moyers has been exploring geology.

This belief in the efficacy of ideas in the service of good is also what has made him such an extraordinary interviewer. In a world of certainty that forecloses investigation, Moyers has curiosity. In a world of glibness and superficiality, he has a rare temerity of mind. In a world of ego and bombast, he has always been modest and self-effacing. He not only gives a forum to unusual thinkers, he is truly, visibly, interested in what they have to say and in who they are because he believes that their ideas really matter. It is clear that for Moyers, these interviews aren’t a way to fill time or amuse an audience or aggrandize himself, and he obviously has no interest in the “get” -- the hot interview. Instead, they have always been a way to learn how, once again, to make things better by accumulating the wisdom of people who are trying to do just that -- people who are engaging the world. In short, they are a search for moral prescriptions.

None of this is the ordinary language of television, much less the ordinary purpose of television. In providing this kind of discourse, in taking ideas seriously, in understanding that discussion as opposed to declamation is itself a moral activity, and, perhaps above all, in fighting the power structure that so often ignores or defies the needs of ordinary people, Moyers has become much more than a broadcaster or even a moral thinker. He has become one of our preeminent moral authorities -- the man on whom we rely to bring us back to our best values.

That may be precisely what infuriates his right-wing enemies. He has both a goodness and a gravitas they lack. We know that he doesn’t need or want attention, that there is nothing for him to gain personally by battling corporate America or fundamentalist America or our government or the media that so often enable these other forces or any of what he has called “the apologists for people in power,” and that there is much to be lost. Indeed, in 2005, Kenneth Tomlinson, the chairman of the Corporation for Public Broadcasting and a right-wing partisan himself, accused Moyers of “left-wing bias” in an attempt to keep him off the air, to which Moyers, who was retired from television at the time, quipped that his critics “might just compel me out of the rocking chair and back into the anchor chair.” (They eventually did.)

There is no shortage of loudmouths on television. There is, however, a very short supply of soft-spoken moralists -- exactly one. Moyers can speak truth to power precisely because his motives are unimpeachable, his independence firmly established, his respect for ideas and thought amply demonstrated and his populism sincere and grounded in something much deeper than political fashion. All of this has been Bill Moyers’ triumph, but when it comes to television it has also been his albatross. There really is no place for quiet truth on television anymore, only shouted opinions; no place for speaking truth to power, only repeating what power dictates; no place for morality, only strict, self-righteous moralism.

That is America’s loss. Bill Moyers may return to weekly television, even though he is 75 and certainly has paid his dues in full. After all, he has left and come back before. But if he does, he won’t return because he needs it. He will return because we need him. Until then, television will have a gaping hole.

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Gabler is at work on a biography of the late Sen. Edward M. Kennedy.