DETROIT (Bloomberg) — Ohio can’t disqualify provisional ballots cast in the wrong precinct, an appeals court said, upholding an earlier ruling.

The U.S. Court of Appeals in Cincinnati issued the ruling Thursday, the second loss in two weeks for the state in election-related lawsuits.

A lower-court federal judge in August ruled that provisional ballots, used to record votes when eligibility is an issue, can’t be thrown out if they’re filed in the wrong precinct as a result of poll-worker error. Opponents of a 2006 law saying they must be discarded argued that the law would unfairly cause the rejection of thousands of votes in the November election.

Ohio said the law didn’t disenfranchise anyone and allowed a more efficient election. A three-judge panel of the U.S. appeals court in Cincinnati disagreed, finding that the plaintiffs had “shown a likely equal-protection violation.”

Ohio’s secretary of state “failed to present evidence to the district court that other factors besides poll-worker error caused wrong-precinct ballots, and the state offers none now,” the panel said.

“Because the state offers no evidence of alternative causes, we find no clear error with the district court’s factual conclusion that most right place/wrong-precinct ballots result, and will continue to result, from poll-worker error,” it said.

A different panel of the same court on Oct. 5 barred enforcement of a law that cut the number of early-voting days by three for everyone except for members of the military and Ohioans living abroad. The state appealed to the U.S. Supreme Court.

The lawsuit is one of at least 15 pending nationwide over election law limits on issues such as early voting, registration and identification in the run-up to the Nov. 6 vote.

About half of the pending cases are in states where both Democratic President Barack Obama and former Massachusetts Governor Mitt Romney, a Republican, contend they can win. In Ohio, a so-called swing state that no Republican has lost and captured the White House, both Obama and Romney see a path to victory.

Voting laws have been enacted by Republican-dominated legislatures across the country — laws aimed in part at fighting voter fraud, proponents contend. Opponents argue they are an effort to limit votes for Democratic candidates.

Over the past few months, the majority of challenges have been resolved against the laws, including an Oct. 2 decision in which a Pennsylvania judge barred enforcement of the state’s voter photo-identification law until after the election.

The judges hearing the Ohio provisional ballot appeal were all appointed by Republican presidents. Julia Smith Gibbons and Deborah Cook were chosen by George W. Bush; Lee Rosenthal, a U.S. district judge from Houston, by George H.W. Bush.

In the ballot lawsuit, the Service Employees International Union, Local 1, and other plaintiffs sued the Ohio secretary of state, seeking a statewide order that provisional ballots cast in the wrong precinct be counted.

The union argued that rejection of such ballots violates the rights of voters, particularly in locations that have multiple precincts, which are generally in urban areas.

In these locations, casting a ballot in the right precinct is dependent on the poll worker, according to the court filings. Plaintiffs said that accepting these ballots would prevent the disqualification of thousands of votes.

U.S. District Judge Algenon Marbley in Columbus on Aug. 27 ordered such ballot disqualification stopped. In 2008, Ohio rejected 14,355 so-called wrong-precinct ballots, according to the judge’s decision.

Marbley, appointed by President Bill Clinton, a Democrat, said that as a matter of law if a voter casts a ballot in the wrong precinct it’s the fault of a poll worker, unless the voter deliberately refused to go to the right polling place.

To disqualify a voter who used the wrong precinct, the state would have to provide a sworn statement by a poll worker that this happened. The state appealed the decision.

The counting of wrongly cast ballots would “undermine the precinct system,” Fred Nelson, an attorney for the state, said at an Oct. 1 hearing before the appeals court. “If a vote counts even when cast in the wrong precinct, voters will be able to vote on issues that aren’t relevant to them.”

Disqualifying these votes “doesn’t undermine the fabric of the election,” Nelson said, asking the panel to throw out the earlier ruling. “The problem only affects 0.1 percent of all votes.”

Reversing Marbley’s decision would “indisputably result in the rejection of thousands of votes by lawfully registered voters that would otherwise have been protected from disqualifying poll-worker error,” lawyers for the union and a homeless advocacy group said in a filing with the appeals court.

For about 80 percent of provisional votes cast in the wrong precinct, the voters were given the wrong ballots because of poll-worker error, plaintiffs’ lawyer Danielle Leonard told the appellate panel at the hearing. Rejecting these ballots would be “incredibly unfair,” she said.

“To disqualify those ballots after the election is not needed to uphold the precinct voter system,” Leonard said. “It’s the poll workers’ job to tell voters they’re in the wrong place, and it overrides voter error for going to the wrong location.”