It's probably because George Stephanopoulos will be with him onstage at the National Constitution Center in Philadelphia for the 90-minute debate, airing at 8 p.m. EDT on ABC.
"I've got George to hide behind," Gibson told The Associated Press. "This time, whenever I get in trouble I'll say, `George?"' The timing of this debate, as the relative campaign lull leading up to next Tuesday's Pennsylvania primary is ending, made it particularly attractive to ABC.
The network is soliciting questions from Pennsylvania voters but Gibson isn't sure whether they will be used. ABC has also talked to a number of superdelegates and gotten good suggestions about issues to raise that have received little attention so far, he said Friday.
The most interesting suggestion Gibson received for a debate format didn't make the cut. He asked Obama what ABC could do to make this debate different.
"He kind of smiled and said, `We've done it so often that I could do Hillary's lines and she could do my lines and we could each debate as the other person,"' Gibson said. "I said, "Ooh, I think that may be it."' Gibson finds moderating these debates satisfying but not satisfying enough.
"I'm always one of these people who walks away and thinks he could have done better," he said. "The last one went far better than my fears and not nearly as good as my fantasies."