In terms of its success, Michael Moore's "Fahrenheit 9/11" is in uncharted territory. By next week it will probably surpass $100 million in domestic box-office revenues, nearly five times as much as the next-highest-grossing documentary feature -- Moore's own "Bowling for Columbine."

In terms of its politics, though, "Fahrenheit" is strictly par for the course. At a time when the right-leaning Fox News Channel leads all cable news channels, when radio airwaves resound with Rush Limbaugh and Sean Hannity and Laura Ingraham, when bookstores are piled high with the pronouncements of Bill O'Reilly and Ann Coulter and Bernard Goldberg, one form of nonfiction narrative remains determinedly liberal: the documentary film.

Since the political upheaval of the late 1960s, the liberal point of view has predominated among documentaries -- at least those that get a showing in theaters. From films about opposition to the Vietnam War (1974's "Hearts and Minds," 1979's "The War at Home") to slain black leftist or gay leaders (1971's "The Murder of Fred Hampton," 1984's "The Times of Harvey Milk"); from films about the menace of Republican administrations (1992's "Panama Deception," 2002's "The Trials of Henry Kissinger") to the struggles of coal-mining and meatpacking union workers (1976's "Harlan County U.S.A." and 1991's "American Dream"), most documentaries that approach political issues do so from the left.

"I think it's pretty meaningless for a documentary filmmaker to put six years of his life into a film that reinforces the dominant paradigm," explained Mark Achbar, co-director of "The Corporation," a treatise on the evolution of corporate power that opened last week in Washington. "By default, documentary filmmakers are put in a dissident position because we are being critical of what's happening in the world."

"The people who make documentaries very often come from the left," agreed LA Weekly critic Ella Taylor, "mostly because conservatives are not particularly socially conscious people looking to change the world."

Conservatives, of course, might differ with that assessment. And while it might be hard to imagine a captivating 90-minute treatment of, say, the need for a capital-gains tax cut, why couldn't there be, for example, a documentary about the rise of political correctness on American campuses?

Few though they may be, there are filmmakers asking questions like that. David Hoffman, who has been directing documentaries for 40 years, dislikes a lot of what he sees from his colleagues.

"In these documentaries, America is always the bad guy, the power structure is the cause of people's problems, racism is rampant -- they're just too easy to make," Hoffman said. "I despise the assumption of 'the truth' presented by liberal documentary films, which Hollywood just seems to love and always rewards with top prizes."

"Maybe there's a little bit of circularity here," said professor and filmmaker Jon Else, who heads the documentary program at the University of California, Berkeley. "The awards are generally given out by juries in places like Los Angeles, New York, Sundance and Cannes. Those aren't red-state juries, and I don't think that it's a good thing that documentaries are such a blue-state phenomenon."

And films that win awards have a much better chance of being booked at the multiplex.

Even movies that do not overtly espouse a political viewpoint may arise from a "deep questioning of how power is used in a democracy," said Else, director of 1980's "The Day After Trinity: J. Robert Oppenheimer and the Atomic Bomb" and a producer on the PBS civil-rights series "Eyes on the Prize." "For me, that's how you spot" a liberal documentary. Examples: filmmakers questioning the pursuit of convictions in "The Thin Blue Line" (1988) and "Capturing the Friedmans" (2003), and the Arab satellite television network al-Jazeera challenging the American view of the Iraq war in this year's "Control Room."

Not all filmmakers recognize a left-leaning tradition. "The vast majority of documentaries have no political leanings," said Barbara Kopple, the director best known for two Oscar-winning films, "Harlan County U.S.A." and "American Dream." "The ones that do are simply exploring social issues, and different types of storytelling emerge from different crises. So, no, most documentaries do not come from the left."

It is true that most nonfiction films are apolitical. The real meat and potatoes of the documentary industry, Kopple and Else noted, are the works seen on public television, cable channels like A&E and Discovery, and countless direct-to-video releases, where the subjects vary from music to nature to biography.

Still, the documentaries with the highest profiles are the ones that make it to the big screen. And the best opportunity for a documentary to make it into film festivals and, from there, to neighborhood theaters is through a provocative exploration of social, often political, matters.

In the last year alone, there's been the Oscar-winning "Fog of War," in which former defense secretary Robert McNamara, one of the chief architects of America's military strategy in Vietnam, questions the disproportionate price of war; the Oscar-nominated "The Weather Underground," a sober but ultimately sympathetic look at the '60s radical leftist group; Sundance winner "Super Size Me," the anti-McDonald's film about fast-food eating; and "Fahrenheit 9/11," the first documentary to win the Cannes Film Festival's top prize.

Further accentuating the trend, distributors usually release smaller, word-of-mouth-type movies -- including documentaries -- with a limited run in large cities with a tradition of strong art-house audiences. These cities (San Francisco, Boston, Washington and Chicago, along with New York and Los Angeles) tilt more liberal than conservative, which perpetuates the market for more left-leaning documentaries, such as the recent pro-Clinton "The Hunting of the President," the anti-Fox News "Outfoxed," the upcoming "Bush's Brain" and a slew of films critical of the 2000 election debacle and the war in Iraq (including "Uncovered: The Whole Truth About the Iraq War," due out in August).

What concerns Else is that some progressive nonfiction filmmakers, encouraged by the traditional hospitality of their audiences, might overlook evidence that contradicts their thesis.

"If you look at 'Control Room,' it's wiser, more balanced, a film that will generate more productive dialogue in this country," Else said. " 'Fahrenheit 9/11' has a giant ax to grind. It's to Moore's credit that he got those powerful images into theaters, because none of us did, but I feel very uneasy about viewing documentaries as insults. As filmmakers, we can make Gandhi look like an idiot if we wanted to."

Moore's success has brought with it a legion of detractors who have accused him of distortions and outright falsehoods. Awaiting release is "Michael Moore Hates America," a documentary by Mike Wilson, who said he's a libertarian and not a right-wing equalizer.

"I think 'Fahrenheit 9/11' is a well-constructed film, but it's misleading," said Wilson. "And in the end it's going to persuade people to make decisions they wouldn't have normally made, particularly with their vote, which is the most sacred thing we have."

Wilson, who started production a year and a half ago, said his film shows how Moore has manipulated his sources and fudged facts in his movies. (He said he made it for $200,000, most of the money coming from his credit cards, though he received finishing funds from an investor shortly after the trade publication Variety wrote about the project this summer.)

Repeated attempts to reach Moore through the publicist for "Fahrenheit" were unsuccessful.

Wilson said he knows Moore is a filmmaker and not a journalist. But MSNBC host and former Republican congressman Joe Scarborough -- who's been going after Moore ever since "Fahrenheit" came out, dubbing his work "attack filmmaking" -- doesn't believe Moore has earned either distinction.

"If you look at 'Fahrenheit 9/11,' it certainly isn't any more of a documentary than 'The Clinton Chronicles' was," said Scarborough, referring to a 1994 work claiming that Bill Clinton ordered people murdered in Arkansas and made a fortune off drug money. "I was in Congress at the time, and we all ran away from it as quickly as possible -- it was such an embarrassment to Republican members. Hollywood didn't give that trashy piece a second look, but they're embracing 'Fahrenheit 9/11.' "

That's because, director Hoffman said, it's the film's politics that matter to the documentary establishment, such as distributors and festival programmers. Hoffman said he's made 13 documentaries that explore military life, such as "Jimmy Doolittle: An American Hero" and "Second Home: Going to Sea on a U.S. Aircraft Carrier," some of which, he said, scored huge ratings on PBS. None of them, however, has been accepted at Sundance or other high-profile film festivals.

"You show me one film festival that has accepted any pro-military documentary," he said.

Another documentary filmmaker feeling caught in the political crossfire is director Louis Schwartzberg. The Walt Disney Co. refused to allow its subsidiary Miramax to distribute "Fahrenheit." Instead, Disney sent theaters Schwartzberg's "America's Heart and Soul," a panorama that strings together vignettes of happy, creative, hardworking Americans. The film didn't perform well.

"I've never said anything bad about Michael Moore's movie, but they're painting me as some pro-Bush, pro-establishment, right-wing kook," Schwartzberg said.

He said his film was picked up by Disney in November 2002, and that people associated with Moore are seizing on the fact that the studio held preview screenings of the film for conservative groups, which prompted the conservative organization Move America Forward to champion the film early on.

"Because my movie is 35-millimeter, because I wait for gorgeous light, because it's not gritty, I'm being criticized," Schwartzberg said. "Are we so cynical that we can't see a beautiful landscape and not feel that we've sold out?"

Michael Franc of the Heritage Foundation, a conservative think tank, said few conservative organizations would willingly risk the funds and effort needed to make and market a documentary -- especially since a market for conservative films hasn't been demonstrated.

"There were many anti-Clinton films that came out in the 1990s, but their sales fell under the radar -- I don't think any turned a profit," said Franc, the foundation's vice president of government relations. "It's not that it's an infertile ground for conservative filmmakers -- there are people out there doing it. But the problem is finding the right style and technique to make that real breakthrough, and cause a buzz like Michael Moore has."

Scarborough said he is resigned that documentaries will remain a stronghold for liberals, while the less glamorous but wider reach of talk radio continues to serve the conservative crowd.

"It makes sense for Moore to go to his constituency, because if you're a Democrat, talk radio isn't going to be the best place for you to affect the elections," Scarborough said. "You won't see attack filmmaking from the right, because conservatives just don't have a lot of friends in Hollywood."

That's true, film critic Taylor said, but she also gives credit to the age-old calling of the feature documentary form and its historic idealism. "The great documentaries confront social issues, and it's always been the left that has a beef when it comes to social issues, while conservatives, by definition, would like to conserve," she said. "But I wouldn't rule them out."

"The Corporation" is one of several new films that take a liberal slant.