Fulton County Commissioner Robb Pitts has asked a court to overturn the results of last month’s Democratic primary election for commission chairman, saying the county erred in the design of its ballot.

Pitts narrowly lost the May 20 primary to incumbent Chairman John Eaves. But in documents filed late Monday in Fulton County Superior Court, Pitts says the county failed to properly identify the chairman’s race on the ballot. The race was listed as “District No. 7 at large.” But the ballot did not indicate the election was for the commission chairman.

In court documents, Pitts says that omission caused enough “voter confusion and voter disenfranchisement” to warrant a new election. He asked the court to order a new Democratic primary for commission chairman.

In an interview Tuesday, Pitts said the county’s history of botched elections contributed to his decision to challenge the election.

“We’ve done a better job this time than we’ve done in the past,” Pitts said, referring to the primary. “But it’s still not good enough.”

Eaves called the lawsuit frivolous, self-serving and a waste of taxpayer dollars.

“This latest action directly contradicts his campaign identity as ‘a good steward of taxpayer dollars,’” Eaves said. “Instead, Mr. Pitts embarks on an unfortunate pattern of behavior that will result in the unnecessary expenditure of county funds.”

Fulton Election Director Richard Barron referred inquiries to the county attorney’s office, which declined to comment.

The court challenge is the latest twist in an unusually close campaign between two veteran Democrats. The winner will face Republican Earl Cooper in the November general election.

Final results from the primary showed Eave with a 315-vote lead over Pitts. A recount requested by Pitts narrowed the lead to 303 votes out of 45,555 ballots cast.

Pitts asked the court to hold a new election July 22, when a runoff election is scheduled for other races.

According to court documents, about 4,200 voters – or 8.3 percent – cast ballots in the Democratic primary but not in the chairman’s race. The lawsuit says that’s an “alarming” rate, far above the 2 to 3 percent rate typical in elections.

Pitts’ lawsuit says voter confusion caused by the mislabeling of the chairman’s race led to the low vote count. It also faults the county for failing to educate voters on a General Assembly redistricting plan that switched the chairman’s seat from District 1 to District 7.

Fulton County has not labeled the chairman’s race in past elections. Four years ago, for example, the race was identified only as “District 1 at large.”

Charles Stewart is a political scientist at the Massachusetts Institute of Technology and an elections expert. He said it’s difficult to say whether the number of voters who didn’t participate in the chairman’s race is unusually high.

Stewart noted the “undervote” rate in the Fulton chairman’s race was comparable to the rate in the uncontested Democratic Georgia governor’s race, but higher than the rate in the contested Democratic U.S. Senate race, where about 3.7 percent of voters did not cast ballots.

But even if a court believed voter confusion contributed to the outcome of the Fulton chairman’s race, Pitts might not win a new election.

“Judges are very reluctant to overturn election results based on a claim of voter confusion,” Stewart said.

A spokesman for the Secretary of State did not know the last time a Georgia judge had overturned an election, but said it’s an “extremely rare” occurrence.

Fulton County has a history of election problems. Most recently, many voters encountered long lines and confusion at the polls during the November 2012 presidential election.

Fulton officials have said last month’s primary went well, with only minor problems reported.

“Citizens have a right to expect their votes are going to be counted and that all procedures used are fair and transparent,” Pitts said Tuesday.