HE is one of the greatest documentary makers of his time and ours, a folk hero of the left, the scourge of presidents, politicians and business leaders, winner of Oscars in Hollywood, Palmes d'Or at Cannes, and the inventor of the personal-essaystyle feature-length political documentary. His latest film, Sicko, has had a vast amount of publicity. But amid the gladhanding, one awkward question is being whispered: could Michael Moore be running out of steam?

Let us consider the evidence.

His new documentary, on the subject of health care, appears to not be doing such good box office as his last one (Fahrenheit 9/11, on George Bush). While some Sicko reviewers have been kind, others are not convinced: the influential New Yorker says Moore "scrapes bottom" with "superfluous" Sicko.

And this is a film that does not even have a release date in Ireland.

Elsewhere, Moore's methods and past work are under scrutiny while another film about Bush's last election campaign appears to have been placed firmly on the back-burner. Rumours abound, sparked by the man himself, that he may now decide to abandon documentaries to write romantic comedies and straight dramatic features (with a slice of wry) instead. Where else is there left for Moore to go?

The long gestation period for Sicko, Moore's paintball-style attack on the American healthcare system, reflects parallel changes in his own life.

Recognising the irony of an overweight director on a bad diet preaching healthy living, Moore decided to heal himself. He hired a personal trainer and began taking long walks. He also created the Traverse City Film Festival near his impressive home on Michigan's Torch Lake. As he personally reviewed entries, Moore also continued working on fictional screenplay ideas of his own.

This decision to create featurelength film dramas is curious, though, when you consider what happened to his one previous attempt. It was a $10m John Candy comedy called Canadian Bacon, and it cratered faster than a Flint, Michigan job at General Motors, the major employer in Moore's childhood home-town.

Now, it looks like the Big Bopper of ambush journalism wants to turn to romantic comedies and other dramas that will win over the audiences that skip his non-stop assaults on the super-rich, warmongers, gun-slinging vigilantes and heartless drug companies out to grind the faces of the poor. It's as if the sheriff has decided to get out of Dodge City and take up macrame.

Zeitgeist As to Moore's current market value, opening-week numbers in the US suggest that the Grand Guignol on American health-care will attract a smaller audience that his previous hit, Fahrenheit 9/11.

While the director spearheads an admirable political campaign for national health insurance in America, there is evidence that he's having trouble recapturing the zeitgeist that made him famous. Consider one work in progress, a virtual self-parody of his barnstorming American campus tour designed to unseat Bush during the US election three years ago.

Called the 'Great '04 Slacker Uprising', it has the feel of a YouTube video, with endless overthe-shoulder shots of crammed stadiums cheering Moore as he fillets the Bush administration with one-liners. But, in commercial terms, does it work?

Do audiences really want to relive the 2004 election and watch Moore's failed attempt to man the lifeboats for a sinking John Kerry?

The only break he has had so far on this project took place in the autumn at the Toronto Film Festival, where a depressing preview screening was aborted thanks to projection-room difficulties.

Timing is everything in the documentary world and, in the post-Sicko era, documentarian Moore's time may be up.

The fact that Sicko's initial gate is well below his last film is just one indication that his documentary career peaked three years ago. Now that he's a firebrand name, it's harder for him to interview the big guys that he likes to blame for your problems.

In recent years, corporations have posted mug-shots with their office staffs, and even hired profilers to disarm Moore with small talk (such as "how did you lose all the weight?", or "how about those Detroit Tigers?") while security is paged with a silent alarm. In other words, alert chief executives won't follow in the footsteps of the naive Nike leader Phil Knight, who famously made the mistake of telling Moore on camera that his Indonesian 14-year-olds "made sense".

Even worse, for a man who launched his career with Roger & Me in the final days of George Bush senior's reign, and broke documentary box office records with Fahrenheit 9/11 (a film about George W Bush's ineptitude), his beloved Democrats appear to be on their way to retaking the White House.

Moore certainly understands that his vast left-wing constituency has a hard time with his attempts to bash Democrats like Bill Clinton or, more recently, Hillary Clinton. His career on this front has been mixed, to say the least. He ditched an audience of more than nine million that watched his network show TV Nation (shown on the BBC) for Rupert Murdoch's Fox where he promptly mixed it up with broadcast-standards censors and was fired. A self-aggrandising autobiographical film about a book publicity tour, The Big One, sank nearly as fast as the Lusitania. His attempt to launch a talk show featuring OJ Simpson as his first guest bombed.

The pilot for Better Days, a bluecollar sitcom about laid-off workers featuring Jim Belushi (the brother of the late John Belushi) was dead on arrival. And, lest we forget, Moore's script for his only fictional feature, Canadian Bacon, was turned down by 37 studios and production companies. The 38th rashly sank $10m into this drama where Moore ended up in huge battles with his co-producer, and famed cinematographer, Haskell Wexler. The production team was also devastated by the loss of the film's star, Candy, who died shortly after the completion of principal photography.

Following a disastrous testscreening in front of a blue-collar audience, the film opened to pathetic reviews and was quickly pulled from theatrical distribution.

As Moore's first agent, John Pierson, explains, the Clinton years were a disaster for Moore.

When Moore relentlessly attacked "sad, pathetic" Clinton and "his disgusting, hypocritical fellow Democrats" on issues ranging from the bombing of Kosovo to welfare reform, fans were perplexed. Their anxiety grew when he gave the right-winger Alan Keyes the nod for the Republican Presidential nomination in 2000. Keyes won the on-air endorsement of Moore's TV show, The Awful Truth, because he was the first Republican to accept the director's challenge to jump into a portable mosh pit during the Iowa primary. And feminists were apoplectic when Moore predicted, incorrectly, that a Bush presidency would not lead to the appointment of Supreme Court justices likely to tamper with abortion rights.

Should the Democrats regain power, Moore inevitably would find himself tangling with the kind of people who now flock to his movies. Historically, he has been quick to blame the party for selling out their own constituency. And there's another problem with his documentary work: a lack of subtlety that delights many of his fans, but does not draw serious consideration from students of the problem. Negative attacks have made this critic of capitalism rich and famous; unfortunately they have not led to the changes that he advocates. It's likely that, even if America does go for national health care, the final product will fall short of his own political goals.

His new dream appears to be turning out Frank-Capra-style features that deliver a high moral message along the lines of Mr Smith Goes to Washington.

I hit on another reason for Moore's career shift while working on my biography, Citizen Moore: An American Maverick. During more than 250 interviews with insiders central to his career, I discovered that many film-makers had never actually seen a Moore movie.

Neither had close friends in Flint, nor the monsignor who was one of his seminary instructors (not many people realise that Moore is a practising Catholic). Radio talkshow presenters admitted that they had never made it to one of the Moore's films.

Co-workers One reason that people skip his work are rumours about his rough handling of co-workers. For example, one London talk-show presenter told me recently that she skipped Moore's films because she'd heard that he was hard on members of staff at London's Roundhouse Theatre during his 13One and a Half Man show in 2002.

But a more likely reason ties in to the most-asked question I've been hearing from audiences and interviewers: "Are his films documentaries, or are they fictional comedies?" Since Moore gets the credit for making documentaries as popular as dramatic films, let's turn to the first cameraman Michael ever hired, Kevin Rafferty, for the answer. This famed cinema-verite film-maker, who is also George W Bush's first cousin, gave Moore his film debut in Blood in the Face, an expose of the "racialist right". The then Flint journalist Moore scored a major coup when he helped Rafferty's team film a Michigan Ku Klux Klan rally where two lovebirds said their marital vows in a ceremony illuminated by the glow of a burning cross.

Rafferty says that he was stunned when he arrived in Flint and Moore handed him a terrific shot-list for Roger & Me. This was simply not the way cinema verite documentaries were made: a director would create the storyline after shooting was finished. Twoand-a-half years later, Rafferty was even more astonished when he saw that the shot-list had become the movie. Instead of shooting first and editing afterwards, Michael had scripted Roger & Me like a dramatic feature.

Another problem is a lack of trust. There are nagging questions about well-documented omissions.

Moore's decision to leave two filmed interviews with the General Motors chief executive Roger Smith on the Roger & Me cuttingroom floor raises questions he has not answered. The ethics of launching his career by falsely claiming that he couldn't get an interview with the head of General Motors creates a credibility gap. Is it a good idea to rewrite history so that it creates the storyline and publicity necessary to reach an audience that normally skips documentaries?

After years of dodging the subject, Moore confirmed my story that he did, in fact, film an interview with Smith. Then he made the mistake of arguing that this event took place before he began working on Roger & Me.

According to his commentary on the documentary's DVD, shooting began in February 1987, three months before the first filmed interview at a GM annual meeting in Detroit. The second deleted interview, a "home run" according to the soundman, also Moore's friend and Ralph Nader's attorney, Jim Musselman, took place in January 1988.

Even some of Moore's fans worry that he partially stages scenes, undercutting the value of his own work. I spoke about this recently with the cameraman Bruce Schermer, who was paid $5,000 for shooting about 60% of Roger & Me (which was sold to Warner Brothers for $3m). He points out that, during the shooting of the film's famous Christmas Eve eviction of impoverished Flint tenants, Moore was apparently not getting what he wanted. Off camera, he discussed the problem with an unemotional mother.

When Schermer turned his camera back on, this evictee amped-up the scene by screaming.

Corporate greed Of course, Moore has made many important contributions to cinema.

He has done a good job of bringing important social issues such as corporate greed, gun control, George Bush's mistakes leading to 9/11, and a failing American healthcare system, onto the media front-burner. His success has also made it easier for young documentary-makers to find distribution for their work. But the director's success also depends on his ability to start an argument that won't die.

Even before its general release, Sicko has resurrected unresolved controversies. For instance, Moore's contention that Jewish editors at Mother Jonesmagazine engineered his 1986 firing because he didn't want to publish a story critical of Israel makes him sound paranoid.

Controversy, says his former employer Ralph Nader, is Moore's oxygen. In the case of Fahrenheit 9/11, Moore's attempt to derail Bush's 2004 presidential bid, he was able to turn the Walt Disney Corporation's 2003 decision to not distribute the film into a lastminute 2004 publicity bonanza that hyped the movie's release. In his rush to accuse the company of censorship, the director didn't mention that Disney actually held onto its share of the movie, earning an estimated $30m . . . more than Moore's estimated $21m.

Throughout his career, Moore has been the master of constructive failure . . . turning defeat into a publicity windfall that guarantees career advancement. His firing at Mother Jones brought his reverse HoratioAlger-style story to the pages of The New York Times.

His alleged inability to interview Roger Smith created a marketable Don Quixote hopelessness, and one of the most fascinating films ever made on capitalism. His latest letter from the US Treasury Department questioning his Cuban mercy mission for ailing 9/11 firstresponders guarantees a bigger box-office.

But, by his own admission, the ability to get the results he wants . . .

saving the jobs of GM workers in Flint, halting corporate downsizing and foreign outsourcing, stopping the escalating cycle of gun violence or defeating George Bush . . . creates an impressive argument for his journey into the world of dramatic features.

Will these new films lure audiences that have skipped his famous documentaries? Might they end the ceaseless, at times painful, debate over the truthfulness of his work? And, through fictional features, might he be able to dislodge the black hats on his personal axis of evil? With his firebrand name, Moore's future dramas could work nicely. Think about the possibilities: Love Boat on The Detroit River, Desperate Rack and Pinion Assemblers, Idi Amin in Love, or an Israeli musical called Begin the Begin? Shining the spotlight onto the dark recesses of the American dream is his special gift. Perhaps now he is ready to take on the world and win over those who have skipped his pioneering work.

Roger Rapaport is the author of 'Citizen Moore: An American Maverick', published by Methuen