Networks walk a tightrope over crowded debates

"You have to treat all of the candidates the same," said Sam Feist, CNN's current Washington bureau chief. "If you're going to invite them, you have to treat them the same, particularly with the fluidity of this race."

Except for some quick follow-up questions, moderators at recent debates aired on CNBC and Fox News Channel made a conscious effort to ask each candidate onstage to address one issue at the start of their debates. Fox said it tries to treat each candidate equally; NBC News would not discuss its debate policies.

An examination of transcripts for four debates (one each by CNN, CBS, Fox and CNBC) revealed that Romney, generally perceived as the campaign's front-runner, had the most questions addressed to him. He had 45, with Cain next at 37, Perry at 36 and Gingrich at 35. Santorum and Bachmann had 29 and Paul had 27. Huntsman did not participate in all four debates.

Even the networks that strive for some equality in asking questions can't guarantee equal time on camera. If one candidate specifically criticizes another in an answer, the victimized candidate is generally given rebuttal time. Organizers seem to relish when a couple of candidates go after one another and often let those exchanges play out.

"It's a vicious cycle," Bohrman said. "People who are more in the news have more to say and are paid more attention to, and they have even more to say."