Who could replace Jon Stewart on 'The Daily Show'?

The question of who can replace Jon Stewart on "The Daily Show" seems roughly akin to asking his fans what might serve for the sun.

His passion, wit and boldness make for a magical combination that will be difficult to re-create when Stewart steps away as host sometime later this year.

"The X-factor here is Stewart's charisma. It's significant," said Sophia McClennen, a Penn State professor and author of "Is Satire Saving our Nation?: Mockery and American Politics."

The "Daily Show" boot camp has graduated a number of impressive talents who might prove to be worthy of the host chair, McClennen said, counting John Oliver first among a group including Aasif Mandvi, Samantha Bee and Jason Jones.

There are outsiders who certainly have the comedic chops. But do they have the star power and the backbone to speak punchlines to power, and on a nightly basis?

Looking over the possibilities, here are some candidates to consider:

— Oliver. He's top of the list for a reason: He proved he could emerge from the "Daily Show" ranks and succeed as host when Stewart took a movie-making break. Oliver and his dimples defected to HBO, but his return home would be triumphant.

— Tina Fey or Amy Poehler, paired for efficiency's sake given their frequent collaborations. Like Stewart and Oliver, they've got the likability that helps make hard-hitting satire palatable — and how about at least one woman in late-night TV?

— Chris Rock. Brilliantly funny, certainly fearless. He wrote an essay about being black in an entertainment industry that is "kind of racist" in its hiring practices — although he said he wasn't being political at all, adding, "that's Stewart, that's (Bill) Maher."

— Seth MacFarlane. He's a writer, performer and singer who can summon the juvenile glee, if not the artfulness, that Stewart employs to leaven the angst. And he could bring a sidekick, his devilish movie creation Ted the teddy bear.

— Jessica Williams. A "Daily Show" player whose titles include "senior youth" and "senior Beyonce" correspondent, she's brimming with energy and edgy charm. Whether she has the experience and heft to step into the center ring is an open question.

— Joel McHale. The "Soup" host already balances his "Community" sitcom role with a host gig, so why not step it up? He's quick witted, lovable and has a following that encompasses the frat-boy demo that is undeniably part of the "Daily Show" fan base.