"When you said that you did this for others, what can only be called preferential treatment for President Bush, would you describe it as that?" Rather asked Barnes in the DNC ad.

The day after Rather's interview with Barnes was aired on "60 Minutes II," the Texas Democrat's daughter Amy told WABC Radio's Monica Crowley that her father had confessed privately he made the story up to sell a forthcoming book.

The DNC-Rather ad also cites documents purporting to show that Bush missed six months of National Guard service in 1972 - though it's not clear if they're the same documents that have been determined to be forgeries by numerous document authenticators.

When the New York Post asked an unnamed CBS executive over the weekend if the forged document's source had ties to the Democratic Party, he replied, "I can't answer that" — and hung up.

Meanwhile, forger-turned-FBI consultant Frank Abagnale, who was played by Leonardo DiCaprio in the 2002 Steven Spielberg movie "Catch Me if You Can," has weighed in on the CBS forgery scandal, which some have dubbed "Rathergate."

"If my forgeries looked as bad as the CBS documents, it would have been 'Catch Me in Two Days,'" he said in an e-mail, according to the New York Post.

Editor's note: