Ask a late-night talk show host whether he's liberal or conservative and the answer will likely be — what else? — a wisecrack.

That was the kind of response FOX News' Alan Colmes got when he asked Jon Stewart (search), host of Comedy Central's "The Daily Show," that question.

"I'm a Whig, inherent to the Federalists," Stewart quipped. "The gay marriage thing scared me, but that's only because I thought at first it was mandatory."

There is no small amount of political humor mixed with the late-night gags these days. And since many Americans rely on Leno, Letterman, O'Brien and Stewart for their news instead of Brokaw, Jennings and Rather, the question of bias is no laughing matter.

Experts say detecting a bias isn't easy, though, in part because, just as politicians campaign for the most votes, late-night hosts perform to net the most viewers.

"They have to be very careful not to prefer one side to the other, or risk alienating a big chunk of the audience," said Robert Thompson, professor of popular culture at Syracuse University (search).

Thompson said even overtly political comedians, such as CNBC's right-leaning Dennis Miller (search), put laughs above ideology. That, Thompson said, is not only because their careers depend on getting the most laughs, but also because they don't want to risk losing their iconoclastic image.

Brent Baker, vice president for research and publications at the Media Research Center (search), gives another reason comics go for consensus, "The bias is toward telling jokes that people understand."

Late-night hosts have to poke fun at familiar issues and personalities — otherwise the punch line would be lost, he said.

That may explain why there have been more than twice as many late-night jokes about President Bush than rival John Kerry — 555 about Bush this year, compared to 202 about Kerry, according to the Center for Media and Public Affairs. It's because the audience doesn't know enough about Kerry yet.

According to the CPMA, however, the comics may have let slip a slant: According to their numbers, Republicans were targeted in 62 percent of late-night political jokes, while Democrats were targeted in 38 percent between 1988 and 2000.

But Thompson said those numbers are a red herring. "You have to consider any statistics in the context of who the sitting president is at any given era. Bill Clinton is a good example of that," he said.

Indeed, in 1998, during the height of the Monica Lewinsky (search) scandal, political jokes soared to a level not seen before or since.

In Baker's view, however, a liberal bias crops up when hosts interview a "serious" guest. As an example, he cited David Letterman's interviews with Al Gore and Bush during the 2000 campaign. "The Late Show" host was light-hearted toward Gore, said Baker, whereas with Bush, he pitched a few softballs, but mostly grilled the Republican candidate.

"Late Show" executive producer Rob Burnett pushed aside the idea of bias, saying that Letterman purposefully takes the opposite position of guests in order to elicit conversation and get the best television.

"I've known Dave for 19 years and I have no idea who he votes for — and I do know that he votes religiously," said Burnett, who added that the show regularly gets mail from both sides complaining of a conservative or liberal bias.

Similarly, Leno drew fire from critics who accused him of showing favoritism for Arnold Schwarzenegger, a Republican, who launched his campaign for governor of California on "The Tonight Show."

Leno has referred to himself as an "equal opportunity offender," and statistics show that of all the late-night hosts, he comes closest to displaying balance when it comes to targeting politicians from the left and right.

Carrie Simons, a press manager at NBC, said "The Tonight Show" monologue, which is an unusually long eight to 11 minutes, is very carefully crafted and gives Leno more time to target politicians equally.

While the comics themselves aren't up front about their politics, many of their viewers are. A survey by the Annenberg Center for Public Policy of the University of Pennsylvania found audiences for Leno and Letterman tend to be moderate to Democratic, while viewers of "The Daily Show" are often Democrats and rarely Republicans.

"What do you suppose the odds are that Jon Stewart is going to vote for President Bush?" asked former New York Times political reporter Adam Clymer, now director of policy at Annenberg.

In Clymer's view, Stewart's show more often criticizes the Bush administration than Democrats. (Clymer himself was the object of late-night jokes in the 2000 campaign, when a microphone picked up Bush calling Clymer a "major league a**hole.")

Steve Albani, spokesman for Comedy Central, said the show "follows the news cycle." During next week's Democratic convention, for instance, Albani said, the jabs will focus on Kerry and Edwards because they'll dominate the news.

During his years as a political reporter, Clymer's overall observation was that rather than persuading audiences one way or the other, comedians encouraged political apathy.

"The message of late-night TV always seemed very cynical about politicians, doubting their motives, although not in a partisan way," he said. "I'm not saying it isn't good comedy, but ... treating [politicians] as hypocrites and buffoons has an unhealthy impact."

Still, even in a very tight election like this one, Baker said politicians have a lot more to worry about than late-night jokesters.

"Bottom line," he said, "comedians are the last threat to a candidate."