The U.S. Supreme Court on Monday left intact a new Republican-backed law in Wisconsin that requires voters to present photo identification when they cast ballots.
The court declined to hear an appeal filed by the American Civil Liberties Union, which challenged the law.
Voter identification laws have been put in place in a number of Republican-governed states over the objection of many Democrats. Republicans in Wisconsin and other states say such rules are needed to prevent voter fraud. Democrats say the laws are intended to suppress the turnout of minorities and other groups that tend to voter for Democrats.
In October, the court temporarily blocked the Wisconsin law. It did not explain its reasoning at the time, but it was most likely because the statute was being implemented so close to the November election, which could have caused confusion and disruption.
The ACLU had pointed out in October that absentee ballots had been sent out before the November election without notifying voters of the identification requirements.
The Supreme Court has previously upheld the constitutionality of such voter ID laws.
Wisconsin's is one of several similar voter ID rules that have become a political and racial flashpoint across the United States.
A federal judge blocked the state's voter ID law in March 2012 soon after it took effect and entered a permanent injunction in April, finding the measure would deter or prevent a substantial number of voters who lack photo identification from casting ballots, and place an unnecessary burden on the poor and minorities.
The 7th U.S. Circuit Court of Appeals blocked the decision and subsequently ruled in October that the law was constitutional. Wisconsin's Supreme Court upheld the voter ID law in a separate ruling.
The case is Frank v. Walker, U.S. Supreme Court, 14-803.
