Georgia voters Tuesday settled several key primary campaigns besides the heated Republican race for governor, though a narrow finish left one statewide runoff too close to call.

As Secretary of State Brian Kemp won a final showdown with Lt. Gov. Casey Cagle in the GOP contest to succeed Gov. Nathan Deal, voters turned out in Republican runoffs for the two statewide offices that Cagle and Kemp are vacating. One of those races was too close to declare a winner late Tuesday.

Democratic voters, meanwhile, picked the former leader of a national parent-teacher group to challenge Georgia's GOP state school superintendent in November. They also chose Democratic opponents for two Republican congressmen.

Here's a look at Tuesday's down-ballot runoff races in Georgia.

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LIEUTENANT GOVERNOR

A heated runoff for the Republican nomination for lieutenant governor was too close to declare a winner late Tuesday.

Unofficial returns showed former state Rep. Geoff Duncan of Cumming ahead of state Sen. David Shafer of Duluth with nearly all precincts counted. But Duncan's lead was less than 1 percent of the total vote. Shafer will be able to request a recount of the vote if the margin remains that narrow in the official vote tally.

Shafer has served at the state Capitol since 2002 and once was the Senate's president pro tempore. Duncan spent five years in the House. They're competing for a chance to succeed Cagle in the state's No. 2 elected office, whose main job is to preside over the Senate.

Shafer has promoted scrapping Georgia's income tax and replacing it with a state sales tax. Duncan has cast himself as an outsider, despite his time as a state lawmaker, and accused Shafer of profiting from his 16 years in office.

The runoff winner will face Democrat Sarah Riggs Amico, a Marietta businesswoman, in the November general election.

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SECRETARY OF STATE

Republican state Rep. Brad Raffensperger won a primary runoff for a shot at becoming the state's top elections official.

Raffensperger of Johns Creek defeated former Alpharetta mayor David Belle Isle to win the GOP nomination for secretary of state. The winner advances to the fall campaign against Democrat John Barrow of Athens, a former Georgia congressman seeking a political comeback after losing his seat in 2014.

The secretary of state's office is currently held by Kemp, who passed on seeking re-election in order to run for governor.

Raffensperger and Bell Isle were the top vote getters in a four-way GOP primary May 22. Both candidates made upgrading Georgia's electronic voting machines for improved security their top priority.

The secretary of state's office oversees elections in Georgia as well as corporate filings and professional licensing.

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SCHOOL SUPERINTENDENT

A former leader of the National PTA has won the Democratic nomination to challenge Georgia's Republican school superintendent in the fall.

Otha Thornton Jr. of Richmond Hill defeated Sid Chapman of Griffin in the Democrat runoff for state schools chief. The retired Army lieutenant colonel will take on GOP School Superintendent Richard Woods in the November general election.

In 2013, Thornton became the first black man named president of the National PTA. He was endorsed by Arne Duncan, who served as education secretary under President Barack Obama.

Thornton defeated an experienced and well-connected educator. Chapman is a former classroom teacher as well as a past president of the Georgia Association of Educators. He was endorsed former Democratic Gov. Roy Barnes.

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CONGRESSIONAL RUNOFFS

Voters in metro Atlanta picked Democratic challengers for two of Georgia's Republican congressmen.

In the 6th Congressional District, Lucy McBath of Marietta defeated fellow Democrat Kevin Abel of Sandy Springs. A gun-control activist whose teenage son was fatally shot in Florida in 2012, McBath will challenge Republican U.S. Rep. Karen Handel in November.

Handel's victory over Democrat Jon Ossoff in a special election last year capped a $50 million campaign that was the most expensive U.S. House race in history.

In the neighboring 7th Congressional District, Carolyn Bourdeaux of Suwanee defeated David Kim of Duluth. A professor and former director of the state Senate Budget and Evaluation Office, Bourdeaux will take on GOP Rep. Rob Woodall in the fall general election.