Cullen Werwie, the governor's spokesman, said Walker was confident the state would prevail in the case.

"Requiring photo identification to vote is common sense. We require it to get a library card, cold medicine, and public assistance," he said. "Ensuring the integrity of our elections is one of the core functions of government."

The GAB said it would "take steps to suspend enforcement and implementation" of the voter ID law and work with local election officials and the public on Flanagan's order.

The lawsuit is one of several pending in state and federal courts challenging the law. On Monday, Dane County Circuit Judge Richard Niess agreed to allow another lawsuit brought by the League of Women Voters of Wisconsin to go forward, finding that the League is a proper party to bring the lawsuit.

In Flanagan's decision, he wrote that the state constitution establishes voting as a fundamental right. With the photo ID law, Flanagan wrote, Wisconsin now has the "benefit and burden" of the most restrictive voter eligibility law in the U.S.

But the law addresses a problem which is very limited, "if indeed extant," he wrote, and fails to account for the difficulty its demands impose upon indigent, elderly and disabled voters.