Sweet column: Obama, Clinton clash over Novak item. The dish on dirt.

LAS VEGAS — Triggered by an item in Bob Novak’s Sunday column suggesting that Sen. Hillary Rodham Clinton has dirt on Sen. Barack Obama but won’t use it, Obama’s campaign Saturday accused Clinton’s team of using “Swift boat” tactics against him.

Clinton’s camp swung back, denying they were spreading rumors about Obama or that they planted information with Novak, wondering why Obama would want to fall into a “Republican trap” to “pit Democrats against Democrats.”

Starting an unusual series of heated exchanges between the two front-running presidential campaigns was a three paragraph item in Novak’s Sunday Chicago Sun-Times column that says “agents of Sen. Hillary Clinton are spreading the word in Democratic circles that she has scandalous information about her principal opponent for the party’s presidential nomination, Sen. Barack Obama, but has decided not to use it. The nature of the alleged scandal was not disclosed.”

Obama sent out an e-mail calling on the Clinton campaign to renounce the item, which he said was “heavy on innuendo and insinuation,” adding, “The cause of change in this country will not be deterred or sidetracked by the old ‘Swift boat’ politics.

The 2004 White House campaign of Sen. John Kerry (D-Mass.) was savaged by TV ads undermining his military career, funded by a group called Swift Boat Veterans for Truth.

A reason the Obama campaign went on the offensive — or that any campaign might — could be to protect itself from material that could surface later.

Clinton spokesman Jay Carson, in Las Vegas where Clinton was stumping, said “a Democratic candidate should be smart enough not to fall into a trap that he has set to pit Democrats against Democrats . . . if you don’t know how to avoid that in a primary, you are going to be in a world of hurt in a general election.”

Carson said they had no idea what Novak, whom he called a “Republican-leaning columnist” was referring to.

“Let’s think about this rationally for a second. Do you really think Bob Novak will be the repository of information from the Clinton campaign?” Carson said.

Novak, asked to react, said neither he nor his source, who he said was a Democrat, have any more information. Novak said his source passed along what he was told “by people inside the Clinton campaign. It was not specified what it was, and it was said to a Democratic source. Clinton would not reveal it because she is such a good person.”

Obama campaign manager David Plouffe, in a second communique from the campaign, demanded that the Clinton team say if “they have ‘scandalous’ information” they are not releasing. “Yes or no?”

“No and no,” Carson said.

Plouffe replied that Obama’s team will take the Clinton campaign “at their word … But what we don’t accept is their assertion that this is somehow falling for Republican tricks.”

Prodding along negative stories is commonplace in hotly contested races. Obama’s presidential campaign “scored a significant hit” against Clinton “by helping to place” a story about tainted Democratic donor Norman Hsu, according to an article about Obama in the December issue of the Atlantic.

The story, titled “Teacher and Apprentice” by associate editor Marc Ambinder, describes how Obama campaign staffers were “frustrated” because the press was not covering Clinton “in the way they expected it would.”