This story initially ran Aug. 28, 2017 at 8:15 a.m.:

State Rep. Geoff Duncan resigned his House seat on Monday to focus on his run for lieutenant governor, pledging to "expose corruption and wrongdoing" in punchy statement that took aim at Republican rival David Shafer.

Duncan, a Cumming businessman, said in a letter to Gov. Nathan Deal that his resignation would be effective Sept. 18, which would set up a likely special election to represent his seat this year. You can read the letter here.

In a separate dispatch, he took aim at David Shafer, the Senate president pro tem and the leading fundraiser in the contest to succeed Lt. Gov. Casey Cagle. He said Shafer's "political charade will soon be coming to an end" and claimed former Gov. Roy Barnes, a Democrat, helped Shafer raise cash for his race.

"Georgians want big ideas," he said. "They want good, conservative policy over politics as usual. My announcement today allows me to focus my efforts full time on the goal of becoming Georgia’s next lieutenant governor and exposing corruption and wrongdoing that have permeated far too long under the Gold Dome."

Duncan and state Sen. Rick Jeffares are both aiming to derail Shafer, a Duluth entrepreneur who has locked up a range of big-name endorsements in his hunt for Georgia's No. 2 job. No Democrat has yet announced a campaign.

The statehouse crowd has shown Shafer the love as he attempts to climb to the peak of political power. A 15-year veteran of the General Assembly and a longtime GOP activist, Shafer raised $900,000 in the opening months of the race, including $150,000 in contributions from lobbyists and statehouse PACs.

In a statement, Shafer spokeswoman Emily Grosshans said it was "sad to watch Mr. Duncan stoop to insults and wild falsehoods."

"We will remain focused on promoting Sen. Shafer's record of conservative legislative accomplishments as he continues to gain support from across the state," she said.