At the Republican primary contest, which celebrities have come out in support of a candidate? And what is an endorsement really worth for a campaign?
American celebrities get their presidential votes in early
As if the candidates duking it out for the Republican Party's presidential nomination in the US have not taken enough hits already, Chuck Norris charged in with a roundhouse kick.
On the eve of the March 13 primary contests in Alabama and Mississippi, voters picked up their phones and heard the actor and martial artist declaring that of all the candidates, Newt Gingrich "would be the best to do head-to-head combat with President Obama". He added that Gingrich would probably win in "hand-to-hand combat" with the president, too.
Show business celebrities are joining the oddball cast campaigning for the Republican nomination, doubling the spectacle playing out in the United States. The effort has been met with a dubious success rate - seemingly because, like the lacklustre candidates themselves, the endorsers are not exactly A-listers.
There's the rapper Kid Rock, who belted out Born Free for a Mitt Romney crowd in Detroit ahead of the Michigan primary, which Romney narrowly won. There's the entire Duggar family of TLC's 19 Kids and Counting, who have joined Rick Santorum on the campaign trail in several states, most recently Louisiana. There's Jeff Foxworthy, the comedian famous for his "You might be a redneck if" jokes, who joined Romney for appearances in Alabama, where the candidate came in third.
The Republican primary contest is far from the first to bring out the celebrities, says Steven Ross, a history professor at the University of Southern California. Politicians have long courted the stars as roadies.
"At the most basic level, they've been doing this since the 1920s," Ross said. "The main goal was always that celebrities draw attention. And that's what it's always been."
Celebrity endorsements do not directly translate into votes. But the indirect benefits - the free media attention and buzz - make it worthwhile to parade the stars around. It can also help with fund-raising, opening the doors to an elite circle of wealthy donors who know, or want to know, the actor/musician/sportsman concerned.
Ross adds that people who are not usually tuned into electoral politics may take notice if a celebrity gets involved in a campaign.
According to Brian Brox, a political scientist at Tulane University in New Orleans, such endorsements give voters a better sense of who the candidate is, based on the association.
"Celebrity endorsements can provide a signal as to, is this the kind of person I would want to have a beer with? Is this the kind of person I would trust to manage my money? Is this the kind of person I would trust to look after my kids?"
There are a few simple rules to follow when you're soliciting endorsements for your political campaign. One is to know your audience. Norris was a good find for Gingrich, Ross said; he has real traction with southern Republicans. However, that did not prove enough - Gingrich came second in those contests, behind Santorum.
But sometimes, the star route really works. In 2007, when Obama was trailing Hillary Clinton for the Democratic nomination, the chat show host Oprah Winfrey stepped forward and declared her support for him. That influential nod generated more than a million votes for Obama, according to a study by two University of Maryland economists - enough to push him past Clinton and win the race.
There are risks involved, though, on both sides. When Kelly Clarkson, the first American Idol winner, tweeted that she "loved" the candidate Ron Paul, there was a swift backlash because of controversial statements he has made on race and homosexuality. Clarkson had to clarify it wasn't an endorsement, and that she had voted for Obama in the last election. When Romney took to the campaign trail in Alabama with Randy Owen, the frontman of the country band Alabama, he asked him to sing the crowd-pleaser Sweet Home Alabama. But, as everyone in the crowd knew, that song is not by Owen's group at all - it's by Lynyrd Skynyrd.
As much fun as the celeb spectacle may be for observers, neither Ross nor Brox thinks any star has changed the course of this nomination race the way that Winfrey did. Even if the celebrities had all stayed at home, Romney would still be looking like the one to beat.
"I would say there's a very small group of what I could call A-plus-list celebrities, who really can begin to shift an election," Ross says. "None of [these ones] have that kind of gravitas."
Once the Republican candidate is finally official and the race proper for the White House begins, Ross predicts that more celebrities - from both the left and the right - will declare their picks.
"Movie stars, like anybody else, want to be on the winning side," he said.
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