The U.S. Supreme Court on Monday turned away a challenge to Wisconsin's voter identification law, allowing the law to stand and handing a victory to Gov. Scott Walker following a long fight by opponents who say it's a thinly veiled attempt to make it more difficult for Democratic backers to vote.

The law won't be enforced for an April 7 election because it's only two weeks away, but it will be in subsequent elections, the state attorney general said. Walker, a likely 2016 Republican presidential candidate, is a longtime proponent of voter ID requirements and signed Wisconsin's into law in 2011. But it was only in effect for one low-turnout primary in 2012 before legal challenges kept it on hold.

The Supreme Court's decision not to take up the case ends the legal fight, for now. "This is great news for Wisconsin voters," Walker said in a statement. "As we've said, this is a common sense reform that protects the integrity of our voting process, making it easy to vote and hard to cheat."

Democratic critics, as well as a federal judge in Milwaukee who last year declared the law to be unconstitutional, say in-person voting fraud is extremely rare. In his ruling striking down the law, U.S. District Judge Lynn Adelman said there appears to have been one documented case of voter fraud in Wisconsin between 2004 and 2012, and that was committed by a man who obtained a ballot in the name of his deceased wife.

Opponents of the law say its true intent is to make it more difficult for older, poor and minority voters who tend to support Democrats and are more likely not to have the proper ID. The American Civil Liberties Union and allied groups persuaded Adelman to declare the law unconstitutional last year. But the 7th U.S. Circuit Court of Appeals in Chicago later ruled that the law did not violate the Constitution.