Advocate staff photo by Brenden Neville --  State and federal scientists and officials inspect a recently formed marsh island, part of a freshwater diversion project to counteract coastal erosion, during a tour for federal and state coastal restoration representatives hosted by Plaquemines Parish on Tuesday, Oct. 4, 2011, in Venice.

Gov. John Bel Edwards is intervening in a slew of lawsuits filed by three parishes alleging that oil and gas companies have violated their permits and damaged coastal properties over a period of decades — a move that further establishes the state as a major player in the ongoing litigation.

The Edwards administration’s announcement Thursday that it would get involved in the cases comes just weeks after Attorney General Jeff Landry filed similar motions.

While Edwards and Landry have traditionally been seen as on opposite sides when it comes to the oil and gas industry in Louisiana, Thursday’s announcement appears to suggest a new effort on the part of both officials to bring some kind of final resolution to the issue.

What that new cooperation means for the cases filed by Jefferson, Plaquemines and Cameron parishes — or larger efforts to hold the energy industry accountable for coastal erosion caused by nearly a century of drilling and dredging — remains unclear. But it could signal a more unified effort to handle coastal issues and could open the door to a global settlement with the oil and gas companies, something Edwards previously has indicated he would be seeking early in his term.

Edwards said Thursday he had instructed the Department of Natural Resources, which oversees the energy industry, to file a petition involving state government in the cases because they represent a concern that goes beyond the boundaries of the parishes that filed the suits.

“What we know is that the parishes filed lawsuits not just in their name but in the name of Louisiana,” he said. “Our one shot to make sure this is done right and our interests are adequately served by these lawsuits is in intervening.

“I don’t believe we have a choice other than to intervene.”

The suits were filed in recent years by parishes acting on their own behalf, under state laws that allow them to sue for damage in coastal areas. The decision by Edwards and Landry to intervene could potentially move those cases into the state’s hands, putting state officials in charge of how the cases proceed and how any money that is recovered is spent.

“This intervention would ensure that the interests of the state of Louisiana are fully protected and that any money recovered in these suits will be spent on coastal restoration,” Edwards said.

While the state’s involvement — which Edwards said Thursday would bring “all coastal stakeholders to the table” — could cut the parishes that filed the suits and the private attorneys pursuing the cases out of the loop, it also could presage a more concerted effort to bring the industry as a whole to the negotiating table.

Before his inauguration, Edwards said he was hoping to begin negotiating with companies in hopes of reaching a settlement along the state’s entire coast.

“One of the things I said over and over during the campaign is that I, as governor, will convene a meeting of the oil and gas company executives, and we’re going to have a discussion,” Edwards said at the time. “If they don’t want litigation, then they ought to voluntarily step up and do some meaningful restoration, and if they are amenable to that, we can do some wonderful things.”

But, he added, litigation would always be an option if negotiations did not work.

“I firmly believe that if there isn’t at least some implicit understanding that litigation follows an unsuccessful negotiation, there is not going to be a successful negotiation,” he said.

Edwards and Landry are unlikely allies in a suit against oil and gas companies.

While in the Legislature, Edwards was a reliable defender of both the parish lawsuits and a more expansive case by the Southeast Louisiana Flood Protection Authority-East that targeted dozens of oil and gas companies for contributing to erosion through drilling and dredging in coastal marshes.

The energy industry sided with Republican U.S. Sen. David Vitter in last year’s gubernatorial election, but there’s apparently been something of a thaw in Edwards’ relationship with oil and gas since his inauguration, as evidenced by two fundraisers industry associations have held for him this year.

Landry, by contrast, has been an ally of the energy industry who, as a congressman, criticized President Barack Obama for instituting a moratorium on drilling in the Gulf of Mexico following the BP oil spill.

But in a statement released Thursday, he said he “welcomed the administration’s intervention” and referred to a need to balance the economic benefits provided by the energy industry with an “ongoing coastal crisis that threatens our very existence.”

Staff writer Elizabeth Crisp contributed to this report. Follow Jeff Adelson on Twitter, @jadelson.