Columnist Robert Novak stood by his story Monday that the Clinton campaign is spreading the word that it's holding back on dishing dirt on Barack Obama, and charged the Democratic frontrunner with playing "Nixon tricks."
Novak, a FOX News contributor, added that he did not believe there were any Republicans behind the effort — as some have alleged since his column was published Saturday — to force Democrats to fight against each other.
Novak's initial report said: "Agents of Sen. Hillary Clinton are spreading the word in Democratic circles that she has scandalous information" about Obama, "but has decided not to use it. The nature of the alleged scandal was not disclosed."
On Monday, Novak told FOX News that claims that there is actual dirt on Obama might not pass the sniff test.
"This is very similar to the kind of trick that Richard Nixon used to pull, where he would say, 'I know some very bad information about the communists supporting George McGovern, but I can't put that out because it wouldn't be right, but I'm just too good of a guy,' " Novak said.
A message left seeking comment from a Clinton campaign spokesman was not immediately returned.
Novak also said he still had no proof that there really is scandalous information about Obama, only that he's certain that Clinton's campaign told well-connected Democrats that they had such information.
"Now whether there is any such scandalous information, I don’t' know, but what I know is I'm confident in my sources, who I trust. We're told this by Clinton people that there was such information out."
Obama responded angrily after Novak's column was published, challenging Clinton's campaign to come forward with the information, if it exists.
"Sen. Clinton should either make public any and all information referred to in the item, or concede the truth: that there is none. She of all people, having complained so often about the politics of personal destruction, should move quickly to either stand by or renounce these tactics."
He also denounced the attacks as reminiscent of the "Swift boat" campaign against Sen. John Kerry in the 2004 presidential race, in which his supporters say his military record was attacked with unsubstantiated reports by the Swift Boat Veterans for Truth group.
Clinton's campaign has denied any knowledge of the story, and suggested that Republicans might be behind the report. Novak is a conservative columnist.
Clinton spokesman Jay Carson said Saturday that Obama was "walking right into a Republican trap."
But Novak said the claims of Republican involvement are unsubstantiated.
"The whole method of the Clinton campaign is when anything derogatory comes up, they say the Republicans are spreading it. But there was no Republicans involved in any of my reporting on this," Novak said Monday.
Novak also suggested that Obama could use the information to his advantage, especially in the heated primary battle in Iowa, where Obama and Clinton were statistically tied in polls last week.
"Senator Obama's only hope is to portray Sen. Clinton as a manipulative, almost Nixonian-type of candidate who would do anything to win and can't be trusted. Obviously, Senator Obama is in a different position — he must win in Iowa," Novak said, but, "Iowa caucus-goers might be put off by any kind of allegation of dirty tricks on the part of the Clinton campaign."