ATLANTA — When Georgians go to the polls — again — next month to vote in the U.S. Senate runoff, they’ll be participating in a unique — and complicated — state tradition.

That’s because Georgia is the sole state to require runoffs in both primary and general elections. In Georgia, candidates must earn at least 50% of the vote to avoid a runoff.

Some other Southern states have a runoff rule in primary elections – but not for general elections like the one Georgia held this month. (Mississippi recently adopted a measure that requires general runoffs for statewide races that will start with next year’s elections.)

In Georgia, although Democratic U.S. Sen. Raphael Warnock earned about 35,000 more votes than Republican challenger Herschel Walker, neither candidate crossed the 50% threshold because Libertarian Chase Oliver drew 2% of the vote. Walker and Warnock now face a runoff for the Senate seat on Dec. 6.

It won’t be Warnock’s first: He won his Senate seat in 2021 by defeating then-incumbent Republican Kelly Loeffler in a runoff.

Georgia’s modern era of runoffs began when the legislature adopted a new election code in 1964, explained University of Georgia political scientist Charles Bullock. The legislature put the runoff system in place – but excluded the governor’s race.

That presented a problem in 1966, when neither Democrat Lester Maddox nor Republican Bo Callaway could pass the 50% mark in the general election due to a write-in candidate. After court challenges, the state legislature — controlled by Democrats — was allowed to choose the governor. Lawmakers chose party-fellow and staunch segregationist Maddox.

In response, and with Maddox’s support, Georgia voters adopted a 1968 constitutional amendment requiring the governor’s race to go to a runoff in the absence of a clear-majority winner.

The state’s runoff law has not been immune to legislative tinkering since then. Back in 1992, Democrat Wyche Fowler lost his Senate reelection bid to Republican Paul Coverdell in a runoff.

Fowler had earned more votes in the general election but neither candidate crossed the 50% mark. Fowler fell to Coverdell in the rematch. The Democratic-controlled General Assembly then changed state law to require only 45% of the vote to avoid a runoff.

That paid off in 1996, when Democrat Max Cleland drew more than 45% — but less than 50% — of the vote, skirting a rematch and winning a Senate seat outright.

In 2005, the by-then Republican-controlled state legislature and then-Gov. Sonny Perdue changed the law back to the 50% threshold.

That would later prove fatal for another Perdue-family pol, David. The incumbent Republican senator — cousin of the former governor — won more votes than Democrat Jon Ossoff during the November 2020 elections but fell just short of the 50% mark, pushing the race to a runoff. Ossoff bested Perdue by about 55,000 votes in the Jan. 2021 rematch, winning the Senate seat in a runoff upset.

“It cuts both ways,” said Bullock, the UGA political scientist, about the impact of Georgia’s unique general election runoffs on political outcomes.

All Georgians who were registered to vote by Nov. 7 can vote in the December runoff. Early voting will begin Nov. 28.