This is a season of culture lording it over politics. Nearly every day some filmmaker, sculptor, poet, rocker, comedian, mime or videographer offers an artistic vision of the presidential campaign, and usually it's a variation of the same vision -- Beware: Bush will eat your children.

Sam Shepard has just announced that he's rushing his new play into production before the election ("a takeoff on Republican fascism," he calls it). Bruce Springsteen continues on the Vote for Change tour. Philip Roth doesn't mention Bush in his new novel, but because it's also about fascism, the literary establishment assumes the real subject is you-know-who.

In this echo chamber Robert Altman's new series, "Tanner on Tanner," Episode 1 of which airs tonight at 9 on the Sundance Channel, passes as subtle. The series opens with Alex Tanner (Cynthia Nixon from "Sex and the City") speaking on what looks like a slightly outre campaign commercial. "Okay, so George Bush isn't getting semen stains on the carpet, but you're telling me he brought honor to his office? I don't think so," she says, and you hear the heavy breathing of Garry Trudeau, who wrote the script.

But Altman is too self-conscious to stay this blankly political, so pretty soon the mechanics unravel the message. One of the floodlights explodes, glass shatters, Tanner curses, everyone freaks out, and we're off to the endlessly backtracking analysis session that is an Altman project, where everyone's always tripping and starting over and the surface is never smooth.

The rest of the four-part series -- each episode runs 30 minutes -- plays out like one of those dressing-room vanity mirrors, everything peering intently at the different versions of itself. "Tanner on Tanner" is an update of "Tanner '88," Altman's mock documentary about a fake Democratic candidate, Jack Tanner (Michael Murphy), trying to break through in the New Hampshire primary, mixing it up with the real-life Bob Dole and Pat Robertson on the campaign trail.

In the update, his daughter, Alex, now a documentary filmmaker and teacher in New York, has just released "My Candidate," a film about her father's '88 run. When that flops at a film festival, she, too, sets out to do an update. In the meantime one of her film students is filming her filming her film. When they get to the convention, some documentary filmmakers start filming their filming. As director Martin Scorsese says in a cameo, "Everybody's making pictures!"

Like the original, this one blurs reality and drama in a way that leaves you wondering what's spontaneous and what's staged. Jack Tanner wanders around the real-life convention chatting with failed Democratic candidates Dick Gephardt and Howard Dean, shaking hands with delegates who pretend to recognize him. In one great scene, Alex Tanner winds up in a skybox with Alexandra Kerry, who's also making a film. Both interview Ron Reagan, and Kerry gets increasingly annoyed as Tanner asks him vague and intrusive touchy-feely questions.

Kerry's acting, right? This must be a setup. Even if she's never heard of "Tanner '88," surely she knows she's sitting next to Miranda from "Sex and the City." But you never know for sure.

"What is 'My Candidate' really about?" an audience member asks Alex Tanner at the film festival, a question that provokes her to ditch the movie. And the question hangs sort of dangerously over "Tanner on Tanner."

What is this about? Unlike "Tanner '88," this is not at its heart a movie about politics. Away from the chaos of New Hampshire, the cameos with Dean and Gephardt feel spliced in. Plus insights from the original "Tanner" still seem fresher. ("The more you reveal your personal narrative, the harder it is to know what it means," candidate Tanner mused in "Tanner '88." "At the end of the campaign, I looked in the mirror and said, 'Jack who?' ") In the new version Mario Cuomo is allowed to drone on, but Scorsese steals the show.

Altman junkies would say his insistence on uncovering the mechanics of things is deeply relevant in an era of stage-managed politics. But this is an election dominated by conspiracists and bloggers, where everyone is all too willing to look behind the curtain and question the truth. (Almost 40 percent of Kerry supporters say that if Bush wins they will doubt the legitimacy of the election.) "People already know about the mechanics of a campaign, forget all that," Robert Redford says in a cameo, when he's urging Alex Tanner to make a new movie.

Altman chooses as his "Rosebud" scene the one at the convention where the documentarian comes to make a film about Tanner making a film and tells her crew that 40 other documentary crews are working at the convention as well. "It really didn't hit me until we got to Boston," he says. "It's this whole incestuous thing, with everyone making their documentaries. That's what this is all about." Then later: "There's more imitation of life than life."

But this diagnosis seems like an afterthought, and too navel-gazing a mission even for Altman. In truth, skipping between the worlds of politics and filmmaking feels disjointed, and the two themes are ultimately held together only by Nixon, who pulls off a more intense version of Miranda, someone tortured by self-doubt and yet somehow supremely confident.

A real update might have had Alex running for president, a backstage loaded with BlackBerrys, candidates totally emptied of meaning. This one seems driven less by that kind of urgency to be relevant than by nostalgia.

Altman calls "Tanner '88" "the most creative work I've ever done." He pulled off an extraordinary feat by getting together the same cast, 16 years later. And judging by the production notes, they all had a great time at the reunion. The Sundance Channel asked him to revisit "Tanner '88," and in a season when anyone of note has something to say about politics, it must have been irresistible.

Michael Murphy as politician Jack Tanner and Cynthia Nixon as his daughter, Alex, in tonight's first episode of "Tanner on Tanner."Michael Murphy, left, former New York governor Mario Cuomo and director Robert Altman on the "Tanner" set.