Veep candidate Paul Ryan wanted to go by "Mr. Ryan" during his faceoff with Vice President Biden during their debate last October, but ABC News' Martha Raddatz explained why she went with "Congressman" instead.

The day before the debate, Raddatz said she received a call from Romney adviser Ed Gillespie articulating the request. "And I said, 'You think at the beginning I'm going to say, 'And welcome tonight Vice President Joe Biden and Paul Ryan?' " she recalled telling Gillespie, noting that she "wasn't really supposed to be talking to him." Raddatz checked with the Commission on Presidential Debates. "And there was no real agreement," she said.

Gillespie doesn't recall the exchange exactly that way. "I'm not arguing with it, you know? But I worked on the Hill for 13 years, members of the House of Representatives go by 'Congressman' or 'Mr.,' and Paul's preference was 'Mr.,' " he explained. "It was just one of those things that was a loose thread that kind of needed to be cleared up -- how do you want to be addressed?"

Raddatz said it was the only time someone from the campaign reached out to her during debate prep. "Frankly, I just put it out of my head," she said.