MILWAUKEE -

A federal judge in Milwaukee has struck down Wisconsin's voter Identification law, saying it unfairly burdens poor and minority voters.

U.S. District Judge Lynn Adelman issued his long-awaited decision Tuesday. It invalidates Wisconsin's law.

Wisconsin's law would have required voters to show a state-issued photo ID at the polls. Supporters said it would cut down on voter fraud and boost public confidence in the integrity of the election process.

But Adelman sided with opponents, who said it disproportionately excluded poor and minority voters because they're less likely to have photo IDs or the documents needed to get them.

A spokesman for the American Civil Liberties Union says his group is "ecstatic" about the ruling. ACLU spokesman Dale Ho says Adelman fairly interpreted the evidence and his organization feels "vindicated" by the judge's decision.

Republican Attorney General J.B. Van Hollen said he will appeal the federal court ruling striking down Wisconsin's voter identification law.

Van Hollen said, "I am disappointed with the order and continue to believe Wisconsin's law is constitutional. We will appeal."

Van Hollen is at the end of his second term in office and is not running for a third. Jon Richards, Ismael Ozanne and Susan Happ are vying for the Democratic nomination. Brad Schimel is the only Republican in the race.

Schimel said he would appeal the ruling if he were attorney general. Richards says he would let the ruling stand. Ozanne called the ruling a step forward. Happ's campaign had no immediate comment.

Republican Gov. Scott Walker has made the voter ID law one of his top priorities. He said last month that he would call the Legislature into special session to enact a law if courts ruled unfavorably.

Democratic legislative leaders are praising the federal judge's ruling.

Democratic Assembly Minority Leader Peter Barca said Tuesday's ruling is "an important step toward reversing the Republicans' anti-democracy agenda and upholding Wisconsin's proud tradition of high voter turnout."

Senate Democratic Minority Leader Chris Larson said "our freedom to vote has been defended" with the ruling by U.S. District Judge Lynn Adelman.

And Republican Sen. Mary Lazich, chairwoman of the Senate Elections Committee, decried the ruling as "judicial activism."

Adelman said in his ruling there was no evidence of voter impersonation in Wisconsin, and a person would have to be "insane" to try it because of the difficulty and tough penalties.

Wisconsin's law was only in effect for a 2012 primary before a Dane County judge declared it unconstitutional.