Republican David Shafer of Duluth, president pro tem of the state Senate, has filed paperwork to run for lieutenant governor in Georgia.

Documents list John A. Isakson, son of U.S. Sen. Johnny Isakson, as campaign chairman. Bartow Morgan, Jr., CEO of BrandBank, is listed as campaign treasurer.

The moves comes as no surprise, but what remains to be seen is whether any Senate GOP colleagues challenge him. With Butch Miller of Gainesville and Brandon Beach of Alpharetta likely out of the contest, Shafer could consolidate Republican support in the Senate.

State Rep. Geoff Duncan, R-Cumming, is also in the contest, and former Democratic state senator Doug Stoner of Smyrna is looking at a run, too.

Shafer said he spent the last five weeks talking with more than 1,200 Georgians and that their "heartwarming" support encouraged him to run.

A former Georgia GOP executive director, he lost a 1996 bid for Secretary of State before winning a 2002 contest to represent the Gwinnett-based Senate seat. He flirted with a run for lieutenant governor ahead of the 2010 election, when it seemed likely Casey Cagle would run for governor.

With Cagle definitely running for the state's top job - he formally kicked off his campaign on Sunday - Shafer said Friday he's in the race for Georgia's No. 2 gig.

Shafer, 51, would likely center his campaign on slashing state spending. He is known in the statehouse for legislation requiring zero-based budgeting, which supporters say mandates agencies to justify their spending. He also sponsored a constitutional amendment to cap the state's income tax at 6 percent. It was overwhelmingly approved by voters in November.