In the rare funny bit from Fahrenheit 9/11, writer-director Michael Moore plays the song "Believe It or Not" - the theme to the '80s-TV superhero satire The Greatest American Hero - over the sight of George W. Bush's "Mission Accomplished" moment on that aircraft carrier more than a year ago. This kind of savvy mass-culture coup has made Moore a hero to grass-roots audiences and populist hipsters alike. The excruciatingly apt lyrics include, "Flying away on a wing and a prayer/ Who could it be?/ Believe it or not it's just me."

Fans of the TV series will grasp the pertinence behind the lyrics: William Katt played a high school teacher who lost the instructions to his alien superhero suit and learned to use it by trial and error. That description fits the negative view of Bush as a man with limited foreign-policy experience who ignored the counsel of predecessors and current intelligence authorities and, after 9/11, scrambled haphazardly into world affairs and super-power dominance.

That summary fits Moore, too, despite his international success and acclaim. As a filmmaker, he's still a self-styled innocent who tries to turn clumsiness into charm, public distress and humiliation into political strategies.

With Fahrenheit 9/11, Moore has tackled his most formidable challenges - sinking an incumbent president and stopping an ongoing war. Superficially, the film is more subdued than Roger & Me, The Big One and Bowling for Columbine. Here, Moore is less of an on-screen star, and for long stretches he goes without a joke. But this movie is just as reliant on relentless ridicule of social-political foes and exploitation of misery.

At one point, Moore shows uncharacteristic sensitivity. He depicts the ravages of 9/11 with only the sounds of carnage - the screen stays black for what feels like eons, then comes to life with the stunned, ravaged faces of onlookers. But that sequence puts to shame much of what surrounds it.

The rest of the movie is an uneasy mixture of muckraking, tearjerking and bombastic burlesque shots at Republicans caught preening before they go on TV. The film's big derisive laugh comes with a clip of Bush on a golf course, saying, "I call upon all nations to do everything they can to stop these terrorist killers," before swinging his club and advising, "Now, watch this drive."

Actually, if the film had mined this vein more steadily, it might have been effective, no matter how "unfair." Why shouldn't a leftist filmmaker inveigh against what used to be called "country-club Republicans," knowing that a right-wing filmmaker could tear down "limousine liberals" - or for that matter, "ice-cream-truck liberals" like Moore - the same way?

Too bad this movie doesn't sustain a single tone or argument. All that unifies Fahrenheit 9/11 is contempt for the Bush administration. Moore stuffs everything in, starting with the scandalous election results in Florida. He probably feels he has to if he's going to create a counter-mythology to the official mythology of Bush as the regular-guy leader of an All-American ruling class. (The 2002 documentary Unprecedented does a better job of detailing voter theft in the Sunshine State.) You can sum up too much of the film in the damning clip of Bush at a fundraiser addressing "the haves" and "the have-mores" and quipping that if some call them "the elite," he calls them "his base."

Moore's impressive on-camera expert is Craig Unger, author of 2004's House of Bush, House of Saud. Unger contends that when the U.S. government helped arrange for 140 Saudis (including many bin Ladens) to leave America two days after 9/11, the Bush White House - friendly and financially connected to wealthy Saudis - did them a favor instead of using them to uncover roots of the disaster. Unger's reporting focuses Moore's distrust of planet-wide bonds among privileged families.

A major thread of Unger's book is that the Bushies have cleverly maintained degrees of separation between their energy-company interests and the Saudis. Moore bleaches out any subtlety with a montage of the Bushies and Saudis merrily meeting and greeting for the cameras.

Moore proves that when Bush released a crucial document about his National Guard service, he blacked out the name of James R. Bath, a Texas buddy who became the American front man and airplane broker for several important Saudis, such as Osama bin Laden's half-brother, Salem bin Laden. Moore also achieves an apex of verite journalism when Secret Service agents interrupt to ask him why he's filming the Saudi Arabian embassy.

But Moore fails to contrast the Bush-Saudi connection (and a shakier Bush connection to the Taliban) with the Bush family's other global relationships. And, unlike Unger, Moore ignores unpleasant facts that don't fit neatly into his argument, like one Arab estimate that Saddam Hussein murdered between 1 million and 1.5 million people. Moore wants to convince viewers that everything Bush's government has done was designed partly to deflect attention from Saudi Arabia as a breeding ground for terrorists, like 15 out of the 19 men who hijacked the planes on 9/11.

He pastes Bush and company's heads on the TV Cartwright family's bodies and introduces the war in Afghanistan with a parody of the opening credits from Bonanza. He makes the Afghan conflict seem as ludicrous as the excesses of the Patriot Act. As in Bowling for Columbine, Moore attacks a state-imposed culture of fear and deploys his own scare tactics, taking testimony from a lonely Oregon state trooper about our vulnerable Northwest coastline. The film jumbles broadsides and farce - notably a clip of John Ashcroft singing one of his ear-shriveling rah-rah ditties, "Let the Eagle Soar" - before settling into a blanket outrage that could apply to any war, no matter how just.

Despite the silly and demeaning juxtaposition of Iraqi woe with Britney Spears' vacant declaration of support for Bush, the movie's most potent moments record war damage on all sides. Fahrenheit 9/11 raises the legitimate question, why shouldn't there be a place in American media for adults to see the human cost of battle? The bloody, broken or incinerated bodies, the demoralization of troops, the terror of insurgent explosions on the one hand and nocturnal American raids on the other - these should be respected as facts, not ignored for morale-boosting purposes.

Of course, many viewers would rather digest this material with guides more reliable than Moore, who mouths gassy platitudes about "immorality breeding immorality." He can't resist milking his most touching and eloquent bereaved witness for maudlin and firebrand effects. This patriotic American working mother, from a multicultural, multi-racial family, encouraged her children to join the military to broaden their opportunities and horizons - and then lost a son.

Unfortunately, her plight inspires one of Moore's abrasive man-in-the-street stunts: accosting congressmen and trying to persuade them to get their kids to volunteer for the Iraq war. (Only one congressman has a child fighting in Iraq.) Moore confronts (among others) Mark Kennedy, a Minnesota Republican, who in reality declared that he'd be happy to cajole his colleagues, "especially those who voted for the war," then noted, "I have a nephew on his way to Afghanistan." In the movie, all we see is Kennedy reacting to Moore's offer with a bizarre look of disbelief.

The problem is not merely that Moore preaches to the choir. It's that, at his worst, he's so bumptious and bullheaded that he helps keep that choir small and strident. In Fahrenheit 9/11, Moore is so anti-Bush that he becomes a Bizarro-world version of Bush himself: tone-deaf, spluttering, incapable of framing an intelligent debate.