With the 2016 presidential elections just around the corner, the United States Supreme Court on Monday announced that it would not examine the constitutionality of a state law requiring voters to show photo identification before casting a ballot.

The justices had been asked to hear a challenge to a 2011 voter photo ID law enacted in Wisconsin. The action clears the way for Wisconsin officials to begin asking for photo ID at the polls, but it is not clear if the statute will be enforced in the state’s general election on April 7.

Supporters of the Wisconsin measure say it helps prevent voter fraud and fosters public confidence in the election process.

Opponents argue that requiring someone to show a drivers license or other photographic proof of identity is a substantial burden to would-be voters – particularly among minority and low-income citizens who may lack the required photo ID or the underlying documents necessary to obtain one.

A federal judge estimated that as many as 300,000 Wisconsin voters, or 9 percent of registered voters in the state, lack the requisite ID.

“This case raises issues of profound national importance,” Washington appellate lawyer Lisa Blatt wrote in her brief on behalf of those challenging the Wisconsin law.

“Millions of registered voters, disproportionately African Americans and Latinos, lack a qualifying photo ID needed to vote under laws in Wisconsin and other states,” Ms. Blatt said.

She said such voters face “substantial or insurmountable burdens to obtain a qualifying photo ID.”

The Supreme Court justices offered no comment or explanation with their order rejecting the case.

The Wisconsin attorney general’s office urged the high court to reject the challenge. The office argued that the US Supreme Court had upheld the constitutionality of voter ID laws in a 6-to-3 decision in a 2008 case called Crawford v. Marion County Election Board. The decision upheld a photo ID law in Indiana.

Assistant Attorney General Clayton Kawski said in his brief that the Indiana and Wisconsin laws are similar, except that it is easier to obtain a free ID in Wisconsin.

Because an appeals court panel upheld the Wisconsin statute, Mr. Kawski urged the Supreme Court to bypass the Wisconsin case and allow the appeals court decision to stand.

He said there was no split among the federal appeals courts on the photo ID issue, and that the high court should allow similar cases to continue to percolate in the lower courts.

“By the 2016 elections, a circuit conflict may emerge warranting this court’s review, or circuit consensus will continue, militating against review,” Kawski wrote. “Now is not the time to take up these issues.”

Currently, 31 states ask would-be voters to present some form of identification before being permitted to cast a ballot. Of those, seven states maintain a strict photo ID requirement. They are Georgia, Indiana, Kansas, Mississippi, Tennessee, Texas, and Virginia.

Wisconsin will become the eighth such state when the courts lift a hold placed on the statute while the underlying case was being considered.

Lawyers with the American Civil Liberties Union said they were seeking an emergency order to keep the law temporarily on hold.

“Although the Supreme Court has declined to take this case, it previously made clear that states may not impose new requirements for voting in the weeks before election day,” Dale Ho, director of the ACLU’s Voting Rights Project, said in a statement.

“The situation is even more compelling here because absentee ballots have already been mailed out for the April election, and early in-person voting has begun,” he said. “Imposing a new restriction in the midst of an election will disenfranchise voters who have already cast their ballots. It is a recipe for disaster.”

Penda Hair, co-director of the Advancement Project, called the Supreme Court’s action “a huge step backward for our democracy.”

The issue of voter ID has divided Republicans and Democrats. Most photo ID statutes have been passed by Republican-majority legislatures claiming an attempt to fight voter fraud.

Democrats counter that voter impersonation fraud is as rare as being struck by lightning. They say the real reason Republicans pass voter ID laws is to disenfranchise poor and minority voters who tend to vote Democratic. Such voters are less likely to possess the required form of ID and face significantly higher burdens while trying to obtain it.

In her brief, appellate lawyer Blatt disputed Wisconsin’s claim that the lower courts were largely in consensus in upholding voter ID laws.

“Far from a ‘consensus,’ jurists throughout the country vigorously disagree about the validity of restrictive voter ID laws,” she said. The lawyer noted that after a three-judge appeals court panel upheld the Wisconsin law, the full Seventh US Circuit Court of Appeals split 5 to 5 on whether to vacate the opinion and re-hear the case.

She said that federal judges in Wisconsin and Texas, as well as state courts in Missouri, Pennsylvania, and Arkansas have struck down voter ID laws.

Kawski said that in addition to decisions by the Chicago-based Seventh Circuit upholding voter ID laws in Indiana and Wisconsin, the Atlanta-based Eleventh Circuit has upheld an ID law in Georgia, and the San Francisco-based Ninth Circuit has upheld an ID statute in Arizona.

The assistant attorney general added that state supreme courts in Wisconsin, Georgia, Indiana, Michigan, and Tennessee have upheld voter ID laws.

Two other voter ID cases are pending in the appeals courts and are likely headed to the Supreme Court. One involves a challenge at the Fourth Circuit in Richmond, Va., to a voter ID law set to take effect in North Carolina in January 2016. The second is a challenge to the Texas photo ID law, which is now pending at the New Orleans-based Fifth Circuit.

The Wisconsin case was Frank v. Walker (14-803).