However, many are not sure whether overtly political personalities will have much effect on the Bush-Kerry election. Conventional wisdom says they "preach to the choir" because their ideological messages often attract politically active fans who already agree with them. After all, Bill Clinton twice won the presidency even as Limbaugh and others bashed him, Talkers publisher Michael Harrison notes.
But could it be different for traditionally non-political entertainers, such as Springsteen and the shock jock Howard Stern, who is heavily campaigning on the air for Bush's defeat? Some think it may.
"The people who listen to Stern are people who are not necessarily political zealots," Harrison says.
Though Springsteen may have grabbed the biggest headlines, he is not the first musician to speak out on the upcoming election or the merits of the war in Iraq.
A handful of country music stars, though perhaps not explicitly endorsing Bush, have released hawkish songs about U.S. military action, such as Toby Keith's "Courtesy of the Red, White and Blue (The Angry American)."
The anti-Bush musical forces may be more vocal. Hip-hoppers have participated in minority voter-registration efforts, and punk rock acts have put out anti-Bush compilations out under the title, Rock Against Bush. Other big-name rockers will appear on a fund-raising compilation for progressive causes, Future Soundtrack for America.
In October, just before Election Day, Springsteen will be among more than 20 musical acts — including the Dave Matthews Band, Pearl Jam, R.E.M., the Dixie Chicks and John Mellencamp — who will simultaneously tour presidential battleground states in MoveOn PAC's "Vote for Change" get-out-the-vote campaign.
Another well-known musician, Steve Earle, has an album featuring critical songs about Bush and Iraq, and told ABC News' Nightline it is an artist's job to sing about politics and opinions.
"We're citizens that communicate," he said. "That's what we do. The idea that artists are unqualified to comment on the society they live in is a relatively new idea that as far as I know, was invented by right-wing talk radio and this administration. I've always thought that was my job."
Just as Springsteen is not the only newly political rocker, the anti-Bush Fahrenheit 9/11 is not the only politicized documentary, though it is by far most successful one.
Moore's film has been attacked over alleged inaccuracies, some of which may be outlined in Michael Moore Hates America, a forthcoming documentary film.
There also have been other liberal-oriented documentaries, such as the MoveOn-financed Outfoxed, critical of the Fox News Channel, and The Hunting of the President, decrying the Clinton impeachment. Still expected is a documentary on John Kerry by George Butler, best known for the 1977 hit, Pumping Iron.
Some cite anti-conservative political messages in mainstream films such as the box office hits The Manchurian Candidate and The Day After Tomorrow. And this fall, Team America: World Police will satirize Bush foreign policy, while Silver City may echo elements of Bush's background as the black-sheep son of a political family runs for governor.