“They're blatant lies. Blatant lies,” Melancon said. “I'm getting calls and people cussing at my staff, and I tell (my staff) I won’t be offended if you tell them back exactly what they’re telling you and just slam the phone and tell them, ‘Don't call here any more.’ (My staff) doesn't have to take that kind of abuse."

After voting against using “deem and pass” for the healthcare bill, Melancon later voted against a resolution condemning its use. But on the vote that actually had bearing on the healthcare bill – the former – he stood with Republicans against the maneuver.

That didn’t stop Vitter’s campaign from using the later vote to launch a series of attacks and fundraising appeals.

“Did you know that Charlie Melancon is SUPPORTING Nancy Pelosi's ‘deem’ scheme to pass the big Obamacare bill into law without a direct vote by the House of Representatives?” says a Vitter fundraising e-mail.

A pop-up ad on Vitter’s website read: “And instead of demanding a direct vote on Obamacare before it becomes law, Melancon supported Pelosi’s ‘deem scheme.’”

Sources confirm Vitter’s campaign has also done robocalls using similar language.

On the vote that had bearing on the use of “deem and pass” on the healthcare bill, Melancon was one of 28 Democrats to vote with Republicans against using it on the healthcare bill.

Later, Melancon voted against a resolution from House Minority Whip Eric CantorEric Ivan CantorEmbattled Juul seeks allies in Washington GOP faces tough battle to become 'party of health care' 737 crisis tests Boeing's clout in Washington MORE (R-Va.) seeking to condemn Democratic leaders for the use of “deem and pass.” But Cantor’s resolution was a largely political and symbolic measure with no actual bearing on the use of the maneuver in the healthcare debate.

Cantor’s resolution disapproved of the “malfeasant manner in which the Democratic Leadership has thereby discharged the duties of their offices.”  Ten Democrats voted against it, but Melancon wasn’t one of them.

Vitter’s claim appears to be technically accurate, or at least justifiable. But Melancon can just as easily point out that he voted against “deem and pass” on the healthcare bill.

Melancon, who has thus far held his fire on Vitter’s “serious sin” with a prostitute in 2007, began calling into question the senator’s integrity.

“(Vitter’s) never been honest with you; he’s broken faith with Louisiana, he lied about who he is,” Melancon said. “You think he's going to tell the truth about me? I mean, give me a break.”

Vitter spokesman Joel DiGrado said Melancon’s vote on the Cantor resolution speaks for itself.

“Charlie Melancon and his allies can try to spin this any way they can, but a member of Congress’s main responsibility is to vote, and in this instance he voted to support Pelosi's underhanded ‘deem and pass’ tactic to enact Obamacare without an up or down vote,” DiGrado said.

Molly Hooper contributed to this report.