WASHINGTON (Reuters) - A federal court ruled on Wednesday that South Carolina may not implement a photo ID law for voters until 2013, in the latest setback for a mainly Republican effort to establish identification rules in several states before the November 6 elections.

A sign is seen leading to a polling place at Powdersville Middle School in Greenville, South Carolina January 21, 2012. REUTERS/Eric Thayer

South Carolina joined Pennsylvania, Texas and Wisconsin as states with voter ID laws that have been blocked or deferred by state or federal judges.

A three-judge panel in U.S. District Court in Washington said unanimously that South Carolina’s law would not discriminate against racial minorities. The U.S. Justice Department had argued the measure ran afoul of the Voting Rights Act of 1965, a landmark of the civil rights movement.

But the judges said there was too little time to put the law into effect this year, and added they might have blocked the law entirely if South Carolina had not pledged to give wide leeway to voters who cannot comply.

Republican governors and state lawmakers across the country pushed many of the laws over the past two years requiring voters to show a photo ID, but the political fight over the rules has grown fiercer as Election Day nears.

Proponents say the laws are needed to deter fraud, although examples of in-person voter impersonation are rare. Democrats argue the laws are intended to depress turnout among groups that support them, such as African-Americans.

At a trial in Washington in August, the state said it would accept at face value any honest excuse from voters without a photo ID and allow them to vote if they sign an affidavit.

Without that assurance, the law “could have discriminatory effects and impose material burdens on African-American voters,” wrote Judge Brett Kavanaugh.

The South Carolina decision is unlikely to have an impact on the U.S. presidential race, as Republican challenger Mitt Romney is expected to beat Democratic President Barack Obama easily in the conservative state.

EVOLUTION IN LAW

Another judge, John Bates, wrote that “an evolutionary process has produced a law that accomplishes South Carolina’s important objectives while protecting every individual’s right to vote.”

He added that such an evolution showed the vital function of the Voting Rights Act’s strict requirements, which the U.S. Supreme Court could weigh in on soon in a separate case.

Under the Voting Rights Act, certain jurisdictions with a history of discriminatory election laws, such as South Carolina, must submit proposed election changes to the Justice Department or to a federal court for approval.

South Carolina Attorney General Alan Wilson said the state would take a broad view of what is an excuse for not having an ID, such as being busy with work. “That’s just one of a billion examples,” Wilson told Reuters.

The state always planned to give voters leeway, Wilson said. “The court forced us to do nothing, actually,” he added. “The court agreed with our position that we were going to interpret it broadly in favor of the voter.”

As of April, about 130,000 registered voters in South Carolina lacked a photo ID they could use in an election.

The law includes an offer of a free photo ID, available in each county, another fact the judges cited in clearing the law.

“We want everyone that wants to vote to be able to vote,” South Carolina Governor Nikki Haley said in a televised news conference on Wednesday.

The state offered to drive people to the Department of Motor Vehicles to get an ID, Haley said, “and out of all the thousands of people that they claimed we were disenfranchising, 23 people called us.”

MORE MONITORING

The U.S. Justice Department challenged South Carolina’s law, as it did Texas’ law, because it said black voters and other minorities were more likely not to have a photo ID.

The department on Wednesday welcomed the “broad modifications” the court required to the South Carolina law, spokeswoman Dena Iverson said in a statement.

If the law goes into effect, the department “intends to monitor its implementation closely to ensure compliance with the court’s order,” Iverson said.

State photo ID requirements that are less strict, such as laws in Georgia and New Hampshire, have had more success overcoming legal hurdles.

“Courts are making states demonstrate that these laws will not disenfranchise people - not looking at it in theory but looking at it in actual practice,” said Jon Greenbaum, chief counsel for the Lawyers’ Committee for Civil Rights Under Law. The committee opposed the South Carolina law.

The case is State of South Carolina v. United States of America and Eric Holder Jr., U.S. District Court, District of Columbia, No. 1:12-cv-203.