Why Did 'Idol' Bump Candidates?

Last night's special episode of "American Idol" featured a slew of stars, from Brad Pitt, who received a standing ovation, and Reese Witherspoon, speaking on behalf of the Children's Defense Fund, to Miley Cyrus, Sting, Keifer Sutherland and even British Prime Minister Gordon Brown.

But who didn't make the cut at the end of the two hours?

Hillary Clinton, Barack Obama and John McCain.

The presidential candidates all taped appeals for charity for "Idol Gives Back," but when the special telethon edition of the popular singing contest show went on too long, that segment was cut and was bumped to tonight's show.

The appearance of the White House hopefuls demonstrates their desire to engage pop culture and the show's massive audience.

But would it have helped or hurt the show's ratings?

Last night's viewing audience for the show, which advertised the expected appearance of the candidates, was 33 percent lower than last year's telethon, according to overnight numbers analyzed by television industry blog, TVbythenumbers.com.

Over 17 million watched last night's episode compared with 26.4 million who viewed last year's candidate-free episode, according to the blog. Last year's charity show raised $76 million. Fox said as of yesterday's airing, the show raised $22 million.

"It seriously underperformed this year," says Robert Seidman, the cofounder of the blog. Commenters on his site noted that the lack of an elimination round drove away plenty of viewers last night.

In the past few weeks, the presence of the candidates has boosted ratings for some shows. Of course, these were live appearances rather than the canned clips planned for "Idol."

The week that Obama appeared on "The View," the show's ratings reached a four-week high, according to ABC.

And Hillary Clinton's appearance on "Saturday Night Live," in which she engaged her comedic doppelganger, created buzz for the show and led to cover stories on the long-running program's comeback.

A spokesperson for Fox says that the candidates' taped videos were tied to a longer documentary segment featuring Bono and they were pulled because of time.

"The pieces are all going to run tonight," explained Scott Grogan, denying that the videos were omitted over concern for the show's ratings.

The phenomenon of candidates appearing on primetime specials and late-night comedy shows is not new. Ever since Bill Clinton played the saxophone on the Arsenio Hall show back in 1991, politicians have pulled out all the stops to charm the public.

"Candidates recognize that they need to be hitching their stars to the celebrity wagon," says Stephen Burgard, director of the school of journalism at Northeastern University.

"And American Idol is the 2008 version of Ed Sullivan and Life magazine rolled into one."

Burgard was not surprised that the network would pull the candidates' taped videos. "Everybody would rather see Brad Pitt than John McCain — that goes with the territory."

Part of that stems from viewers' innate understanding that candidates are just politicking and not revealing their true nature, says Burgard. "People have a built-in radar when they watch TV, they recognize that this is the candidate using the venue to pitch their message."