Louisiana’s gubernatorial campaign is at that stage in the movie when we know the shark is out there, but we still haven’t seen it on the screen.

The opposition research is complete and ready to be leaked.

As one Republican candidate’s adviser said, all that’s needed is “for someone to throw the first punch,” and then the mud-slinging melee will be on.

Roger Villere, who chairs the Republican Party of Louisiana, says he’s talked to all the campaigns and has repeatedly asked the candidates to play nice and stick to the issues.

Is that going to happen?

“No,” Villere said last week. “We’re going to have to grin and bear it.”

And so it begins.

For the most part, state Rep. John Bel Edwards, the sole Democrat among the four best-funded candidates, has been left out. This fight is strictly Republican, for the time being at least.

When asked at a recent forum how he differs from U.S. Sen. David Vitter, who was not in attendance, Lt. Gov. Jay Dardenne quipped: “I go to forums even when I don’t know what the questions are going to be. Oh, I have not frequented prostitution.”

During qualifying last week, a college kid showed up in diapers to mock Vitter. Young women dressed up and waved signs criticizing a European trip Dardenne took and Public Service Commissioner Scott Angelle’s affiliation with Sunoco, a Philadelphia-based oil company.

Interestingly, the young woman dressed in construction garb said she wanted to point out that the oil company contributed money to Angelle’s campaign. Actually, the company hasn’t, but he is on the board of directors, which pays six figures, and from which Angelle says he’ll resign, if elected.

The demonstrator refused to give her name or say which candidate she was working for, but after Angelle left, she shed her costume and hung out with Vitter’s supporters.

While the young woman may not have known exactly the basis for her protest, Vitter’s staff made sure the media had documents supporting the claims.

Both Dardenne and Angelle called the attacks petty and typical Washington-style politics.

The Vitter documents insinuated that Angelle charged state taxpayers for travel to an interview to get the Sunoco job. Angelle said he met officials with the company that eventually took over Sunoco to discuss business deals with the state, long before joining the Sunoco board. Also, he noted that Sunoco’s pipelines are interstate and thus regulated by the federal government, not the PSC, so his board job is not a conflict of interest.

Dardenne said the trip being portrayed as some leisurely vacation to Europe was actually a delegation of about a dozen tourism officials from around the state who were meeting with tour operators, travel writers and other officials in a bid to attract more international tourists to Louisiana. (Foreigners spend more money and are more likely to leave New Orleans to tour other parts of the state.)

But Vitter was reacting to the first real punch thrown in the campaign.

A newly formed PAC — whose backers the organizer has so far refused to disclose — bought television time to run a commercial recapping old scandals surrounding Vitter.

As they did in 2010, Vitter’s lawyers cowed the TV stations over an error. A Vitter aide, who resigned or was fired, did not admit to and was not convicted of cutting his girlfriend’s throat, as portrayed in the commercial, but pled to a lesser charge.

Vitter emailed supporters using all the incendiary monikers — liberals, trial lawyers, Obama — to describe the backers of the ad. “They’re actively working for my opponents and launching a gutter attack campaign for them,” Vitter wrote. (He presented no evidence to support those claims.)

However, he was accurate in describing the commercial as stale. It’s a recap of his 2007 acknowledgement of an unspecified sin after his phone number showed up in a prostitute’s files. Vitter was overwhelmingly reelected to the U.S. Senate in 2010.

After the ad, court records were leaked recounting the now-resolved criminal charges faced by aides who work for Dardenne and Angelle.

As the campaign continues and focuses more on what politicians and staffers have done way back when, attention is diverted from issues.

For instance, all four say they’ll convene a special session of the Legislature, presumably within a couple weeks of being inaugurated, to address the problems of a state budget that is falling apart even now. Yet, not one candidate has articulated any serious solutions. They prefer, instead, to mix a little mud with their bromides.

Mark Ballard is editor of The Advocate Capitol news bureau. His email address is mballard@theadvocate.com and is on Twitter, @MarkBallardCNB. For more coverage of government and politics, follow our Politics Blog at http://blogs.theadvocate.com/politicsblog/ .