Sen. David Vitter (R) kicked off his 2010 re-election campaign with a high-profile fundraiser on Tuesday night featuring the biggest names in Louisiana’s Republican Party and even a few Bayou State Democrats.

Aside from filling Vitter’s campaign coffers, the $1,000-a-head event also had a more subtle purpose. Namely, to demonstrate the unity of Republicans behind Vitter’s re-election and to keep would-be GOP primary challengers squarely on the sidelines for the 2010 race.

Any potential vulnerability that Vitter faces next cycle stems directly from his ties to Washington, D.C., prostitution madam Deborah Jeane Palfrey, who committed suicide in May. Vitter has acknowledged that his contact information was among her records, but he has never admitted to paying a prostitute for sex.

Although Vitter was able to sidestep major damage and calls for his resignation in the immediate aftermath of the 2007 scandal, the incident is certain to play into the campaign of any Democratic challenger to Vitter in 2010.

But some state insiders are now wondering if Republicans should dump Vitter before the general election for a GOP candidate with less baggage.

The name mentioned most often for a primary challenge to Vitter is Secretary of State Jay Dardenne (R), who some Louisiana Republicans had hoped would challenge Sen. Mary Landrieu (D) this year. He didn’t, but state Treasurer John Kennedy (R) did after switching parties in 2007. Landrieu ended up winning the race by a comfortable 6-point margin.

This week Dardenne acknowledged that he is the subject of speculation about a primary bid against Vitter, and he said the talk has resulted “in a steady stream of calls and visits from people who have encouraged me to run.”

Dardenne, who did not attend Vitter’s “Mardi Gras in December” event in Washington, D.C., on Tuesday night, said the encouragement he’s received has come from friends and supporters in Louisiana rather than from individuals in Washington.

But, for now at least, Dardenne said he’s happy with his role as secretary of state and he doesn’t have any timeframe in mind for making a decision about the Senate seat.

“I haven’t done anything to advance a candidacy for the U.S. Senate except listen to people who have encouraged me to run,” he said.

But some Louisiana insiders believe that if Dardenne decides to do more than just listen, the popular secretary of state could be as big of a threat to Vitter as any candidate that Democrats could put up in 2010.

“If Jay Dardenne were to stand up and say we need better representation in Washington and he ran in a Republican primary, it would be tough for Vitter,” Louisiana political columnist John Maginnis said this week. Maginnis said part of the interest in Dardenne may have come from disappointment by state Republicans over a missed opportunity in the 2008 Senate contest.

Kennedy “turned out to be a poor candidate,” he said. Dardenne “really would have been by far the better candidate against Mary Landrieu.”

And at a time when national Republicans are seeking to rebrand and rebuild their party and after Louisianans recently saw one scandal-plagued member of their delegation — Rep. William Jefferson (D) — go down in ignominious defeat, Dardenne may be an appealing alternative to Vitter. Jefferson is under federal indictment on corruption charges and awaiting trial. The Senate Ethics Committee dismissed without prejudice a complaint seeking an investigation into Vitter’s conduct.

One other Louisiana Republican who has been mentioned as a primary challenger to Vitter is former state Rep. Tony Perkins, who is president of the Family Research Council, a conservative Christian think tank. Perkins ran for Senate back in 2002, finishing fourth in an all-party primary during Landrieu’s first re-election campaign.

Former Louisiana Gov. Mike Foster’s (R) name has also been floated for a primary run against Vitter, but one Louisiana source familiar with Foster’s plans indicated this week that the former governor would likely pass on such a move.

Vitter supporters argue that his vulnerability is being exaggerated.

In 2004, Vitter won a three-way all-party primary outright with 51 percent of the vote against two Democrats. And despite the D.C. madam scandal in 2007, poll numbers from earlier this summer showed Vitter with a 55 percent approval/38 percent disapproval rating.

Any challenger would be going up against the Senator’s formidable campaign war chest. According to his October Federal Election Commission report, Vitter had just less than $2 million in his campaign account.

But perhaps more importantly, Vitter supporters say he’s done a good job of moving past the D.C. madam scandal and reconnecting with his base.

“He feels he’s done with contrition. He’s focused on delivering results and being the conservative firewall against an increasingly liberal Senate,” one Louisiana Republican insider said. “By all accounts, he is doing what he needs to do.”

And as for speculation about Dardenne, the Republican insider said that in recent cycles, “every time there is a vacancy there is always talk about a Dardenne, but it seldom comes to fruition.”

Democrats would love to see a contested Republican primary in Louisiana so that even if the Senator does win his party’s nomination, he’ll be weakened before the general election even begins. That said, Democrats have no clear contenders on the horizon.

Still, they don’t mind playing up the baggage that the Senator carries.

“David Vitter’s problems over the past few years have been well-publicized and they certainly make him vulnerable in 2010,” Democratic Senatorial Campaign Committee spokesman Matthew Miller said.

One Bayou State Democratic operative pointed out this week that Vitter’s vulnerability may be rooted in the fact that the political pendulum in the state is swinging toward Republicans.

“What David Vitter’s problem is is that Republicans are on the ascendancy in the state and you have a lot of very jealous people and they don’t have a lot of seats to move up into,” the Democratic operative said.

The operative added that the best way to judge the depth of Vitter’s vulnerability will be to see if Democrats can entice their top talent in the state to take him on in 2010.

“If Democrats were that strong or [Vitter] was that vulnerable I’d think you’d see [Rep.] Charlie Melancon” (D) enter the race, the operative said.

But, for now at least, Vitter isn’t concerning himself with speculation about who he might face in two years.

“Sen. Vitter is ready to run for re-election no matter who decides to challenge him,” said spokesman Joel DiGrado. “After holding well over 120 town hall meetings throughout Louisiana while serving in the Senate, he understands what reforms Louisianans want him to fight for in Washington.”