Memory does seem in short supply. Before Michael Moore's "Fahrenheit 9/11," there was "The Day After Tomorrow," in which global warming caused catastrophic, if unlikely, disasters. Environmentalists welcomed the movie as a wake-up call about global climate change. Conservatives griped about liberal propaganda.

"The Day After Tomorrow" seemed very much like "The Day After," the 1983 made-for-television film about a Kansas town in the aftermath of a nuclear attack. That, too, aroused liberal hope and conservative fear that it would convert the electorate into a bunch of peaceniks. Neither lingered very long in the public's mind.

Another filmmaker, David O. Russell, is planning to present a war documentary in the fall, along with his re-release of "Three Kings," the George Clooney film about the 1991 Gulf War. Russell says he, too, hopes to have an influence on the election.

And a few weeks ago, the remake of "The Manchurian Candidate" evoked hopes from the left and concern from the right that audiences would associate the Bush administration with the film's corporate conspirators who try to steal the presidency. The original in 1962 had, of course, no political consequence, great fun though it was. The most compelling scene was the fight between the major and the Korean valet. But everybody knew that the guy up there on the screen wasn't really Maj. Bennett Marco, combat officer and martial artist. He was Frank Sinatra, the great singer who had been Angelo Maggio and Danny Ocean. This time Marco is Denzel Washington, and everybody knows who he is, too. He was the Mighty Quinn, Malcolm X and the tough detective Alonzo Harris in "Training Day."

The current plethora of political films and documentaries notwithstanding, the summer blockbuster on any given weekend is more likely to be a sequel to last year's hit animated film or an action thriller that allows its viewers to escape the world for a short while. It still holds true that people go to the movies to be entertained, fully aware that they are seeing artifice, even if it is nonfiction artifice. Nuclear war was unpopular before anyone saw "The Day After," and few Americans needed "The Day After Tomorrow" to persuade them that global warming is real. Let's face it, the number of times a movie has altered public opinion on any issue can be counted on the fingers of no hands.

In fact, if the world of popular culture ends up influencing this campaign, it is likely to be through political activity, not cultural artifice. Bruce Springsteen is not composing a song in support of Sen. John Kerry; he is just going to campaign for him, and he has indicated that he is going to do so by criticizing President Bush's policies, not by attacking Bush personally. Springsteen seems to be a shrewder political analyst than many political analysts.

Alas, too many political analysts have fallen under the sway of popular culture's flourishing academia-journalism nexus. Scores of universities teach popular culture, providing a profusion of professors happy to talk to reporters, who enjoy writing stories about pop culture's political potency.

With talk radio, the 24-hour cable news networks, the Internet and blogging, technology and popular culture have all been offered up as vehicles for revolutionizing presidential politics. This election cycle, the Internet was a useful fund-raising and organizing tool for Howard Dean. Useful but insufficient; even a good tool cannot rescue a poor candidate. Talk radio and cable news are not inconsequential; if nothing else, they help explain the overall decline in the quality of American journalism. But they have not elected anyone.

Neither will "Fahrenheit 9/11," even if the DVD is released in the month before the election. Nor will all the new documentaries on the hero soldiers of the war in Iraq or the one on Kerry. Polls have shown that "Fahrenheit's" impact has been minimal or nonexistent. Most of its audience was anti-Bush before entering the theater, and the other folks are as likely to be repelled as converted. One of the wiser political consultants, David Axelrod, noted that while many swing voters are disappointed with Bush, few dislike him. For them, Moore's blunt polemic could prove counterproductive.

Still, the possibility that this film or another could influence a swath of the voting public has captivated the hopeful and the worried. At least one organization, "Move America Forward," seems to have given birth to itself (or have been fathered by a Republican-connected public relations firm) solely for the purpose of trashing "Fahrenheit 9/11."

That's not to say popular culture has no impact on people. Because of Moore's film, people are still talking about those few minutes when Bush continued reading "The Pet Goat" with schoolchildren after the attacks on the World Trade Center.

Campaigns are won or lost depending on what is happening in the world, and how effectively the candidates campaign. Popular culture is just a postmodern term for entertainment, which is a lot more fun than politics but totally different.