One of Georgia’s worst Capitol Hill nightmares could very well unfold in the weeks ahead.

Longtime U.S. Sen. Thad Cochran announced on Monday that he plans to retire on April 1. That leaves open the chairmanship of the Senate Appropriations Committee, the powerful panel closest to the federal purse strings.

Next in line to succeed the Mississippi Republican is U.S. Sen. Richard Shelby. That means it’s very possible that one of Georgia’s top rivals in its long-running water rights battle with Alabama and Florida could soon end up with much more power to tip the scales.

As Georgia lawmakers tell it, Shelby, R-Ala., has used his position as a senior appropriator to try and give Alabama an edge in the water fight.

Shelby says he’d prefer for the governors of Florida, Alabama and Georgia to hash out an interstate compact outlining water usage – an outcome also pushed by the courts and other stakeholders that has so far proven to be evasive. But he’s also made no apologies for standing up for his state.

"We've gotta protect our interests," he told us last fall.

Until now, Georgia's congressional delegation has been able to band together as a group and effectively block Shelby by going over his head to GOP leaders. They argue that Congress should stay out of this fight as it makes its way through the courts.

But the dynamic could shift substantially if the Georgia delegation is forced to contend with a chairman Shelby. Appropriations chairmen have great power to reward friends by pumping up spending for treasured programs and punish enemies by withholding or slow-walking money.

“It gets a lot harder” to square off against a committee chairman, said U.S. Sen. David Perdue, R-Ga. “I’m hopeful that if Sen. Shelby moves over to become the chair of the Appropriations Committee that we’ll still be able to get to a reasonable resolution on the water problem.”

If not, Perdue said Monday, “we’ll just fight it.”

Behind the scenes, Georgia lawmakers are doing just that as they look to keep water wars language out of a fiscal 2018 government spending agreement leaders want to pass before Cochran’s departure.

Ranger Republican Tom Graves, meanwhile, is running for the House Appropriations Committee chairmanship. He'll need to defeat several popular and more senior Republican colleagues next year to win the position, but if he did it would help boost Georgia's negotiating position.

Shelby wouldn’t step on Cochran’s toes on Monday but indicated he’s eyeing the leadership of the Senate committee.

“I would be interested at the proper time,” he said.

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