Dane County Judge Richard Niess, ruling in a lawsuit filed by the League of Women Voters of Wisconsin, said the law's photo ID requirements are "unconstitutional to the extent they serve as a condition for voting at the polls," the Wisconsin State Journal reported.
The ruling acknowledged voter fraud "corrupts elections and undermines our form of government" and public officials are empowered to address it, but Niess found "voter fraud is no more poisonous to our democracy than voter suppression. Indeed, they are two heads on the same monster."
Cullen Werwie, a spokesman for Gov. Scott Walker, said it was "a shame activist Dane County judges continue to stand in the way of common sense."
"Gov. Walker looks forward to implementing common-sense reforms that protect the electoral process and increases citizens' confidence in the results of our elections," Werwie said.
State Attorney General J.B. Van Hollen said he will appeal Monday's ruling.
The ruling came on the same day the U.S. Justice Department blocked a Texas law requiring voters to show a photo identification, saying the law disproportionately harmed Hispanic residents. The Justice Department in December blocked South Carolina's voter ID law, saying it discriminated African-American voters.
Also in Wisconsin Monday, the Government Accountability Board said more than 931,000 petition signatures have been submitted in the campaign to recall Walker, far exceeding the 540,208 valid signatures required to put the issue up for a vote, The Milwaukee Journal Sentinel reported.
The board also said Monday recall elections must be conducted for four Republican state senators. A hearing is set for Wednesday on determining a date for such elections, the Journal Sentinel said.