ATLANTA — When Gov. Sonny Perdue pitches in next week to help Gov. Charlie Crist of Florida in his bid to become a U.S. Senator, the gesture may be about more than helping out a fellow Republican in a tough campaign.

It’s also a useful political favor when it comes to the three-state water war that has pitted Georgia, Florida and Alabama against one another for rights to water flowing from Lake Lanier.

As Georgia officials work to strike a deal before a federal judge’s deadline that could cut metro Atlanta off from its main drinking water supply in 2012, the state is pulling out all the stops. State legislators last week approved sweeping water conservation bills to show that Georgians were working to control their thirst.

With the clock ticking and the state’s fate left largely to outside forces, observers say Georgia is focusing on politics — perhaps the one thing it can control — to help broker a water deal.

“This is certainly an important gesture to our neighbors,” said Gil Rogers, a staff attorney with the Southern Environmental Law Center. “Georgia needs to show the states, and ultimately the judge, that they’re taking water seriously and not just when there’s a drought.”

For two decades, Georgia, Alabama and Florida have haggled over water, as Florida and Alabama have accused Georgia of withholding too much water from the lake and drying up river flows into their states. At issue are the Apalachicola-Chattahoochee-Flint river basin — which is dominated by Georgia and includes Lake Lanier — and the Alabama-Coosa-Tallapoosa river basin, located mainly in Alabama and a main source of electricity for the state.

Georgia maintained for years that it had the greatest claim to the water in Lake Lanier. But last summer, Senior U.S. District Judge Paul Magnuson ruled that the U.S. Army Corps of Engineers was illegally drawing water from the lake to meet the needs of metro Atlanta’s 3.5 million residents. He stayed the case until 2012 to give Georgia, Alabama and Florida time to work out a water-sharing plan.

The ruling was a humbling blow to the state.

“It finally took Judge Magnuson to force a shotgun marriage for all these groups to come together and finally get something done,” said Will Wingate of the Georgia Conservancy.

It isn’t clear what these gestures will mean, but they could go a long way with Georgia’s neighbors or the judge, who must ultimately authorize whether Georgia can continue to use Lake Lanier for drinking water.

“I don’t think it guarantees authorization, but it is truly a very positive sign to Alabama and Florida that we do take our water resource seriously,” Wingate said.

Perdue isn’t expected to be at the Cobb County event on Monday, but he added his name to the invitation — a cue to his supporters to turn out with their checkbooks. But with Crist facing stiff opposition from tea party favorite Marco Rubio in Florida, he could be grateful for the help, said University of Georgia political scientist Charles Bullock.

There is word that some Georgia tea party supporters could protest the fundraiser Monday, which is being sponsored by U.S. Sen. Saxby Chambliss.

“Crist, because he is vulnerable, may be more willing to talk and negotiate,” Bullock said. “And Perdue is ... offering to help (Crist) with his career crisis and is hoping Crist may be more amenable to helping Georgia.”