The judges also noted the new law allows voters to show a driver's license, ID issued by the Department of Motor Vehicles, a newly-created voter registration card with a photo, a passport or military ID. That expands the list of acceptable ID under existing law, which requires a driver's license, state ID or a voter registration card to vote, the judges said.
The judges declined to let the law take effect immediately, "given the short time left before the 2012 elections and given the numerous steps necessary to properly implement the law."
South Carolina voters who lack the proper photo ID are disproportionately African-American, so proper and smooth functioning of the law "would be vital to avoid unlawfully racially discriminatory effects," according to the decision, written by Judge Brett M. Kavanaugh of the U.S. Court of Appeals for the District of Columbia Circuit. "There is too much of a risk to African-American voters for us to roll the dice," he said.
The judges said the law must be practiced with broad exception for people without photo ID who claim a "reasonable impediment."
"We are fully aware, moreover, that what looks good on paper may fall apart in practice. We expect and anticipate that South Carolina state, county and local officials will endeavor to prevent such slippage," the decision states.
Dena Iverson, a Justice Department spokeswoman, said the administration is pleased the law won't be in effect for this election and in future elections "the Attorney General intends to monitor its implementation closely to ensure compliance with the court's order."
The other judges in the case were Colleen Kollar-Kotelly and John D. Bates of the U.S. District Court in Washington.
Kollar-Kotelly was appointed by President Bill Clinton. Bates and Kavanaugh were appointed by President George W. Bush.
The case number is 2012-203.
Associated Press writer Pete Yost in Washington and Jeffrey Collins in Columbia, S.C. contributed to this report.
Follow Suzanne Gamboa at http://www.twitter.com/APsgamboa