The American Civil Liberties Union wants the Minnesota Supreme Court to keep a proposed constitutional amendment requiring voters to present photo IDs off the November ballot.

The petition, filed Wednesday, claims the wording of the ballot question is misleading and unclear. Supporters say the language is as straightforward as possible, considering it boils a complicated piece of legislation down to a single sentence.

"Voting is one of the most important rights we have, and this amendment aims to take away that right from the most vulnerable, under the guise of a seemingly innocuous photo ID requirement," ACLU of Minnesota executive director Charles Samuelson said in a statement. The ACLU filed the complaint on behalf of several public interest groups and individuals -- including a blind 92-year-old nun.

The question that will appear on the Nov. 6 ballot reads: "Shall the Minnesota Constitution be amended to require all voters to present valid photo identification to vote and to require the state to provide free identification to eligible voters, effective July 1, 2013?"

The complaint focuses on the words that don't appear on the ballot.

Voters might not realize, the complaint alleges, that they would have to show a government-issued photo ID to vote or that the state would have to create a new system of "provisional" ballots for voters without valid identification. Opponents also want the language to spell out the possibility that requiring equivalent identification verification for everyone who registers to vote could make Election Day registration difficult, or impossible.

But the amendment's supporters say the language is perfectly clear. The ACLU has filed similar challenges in other states, and succeeded in derailing a Missouri voter ID amendment over similar wording.

"I believe this is accurate language," said Rep. Mary Kiffmeyer, R-Big Lake, a former secretary of state. The ACLU and Common Cause have brought similar challenges to voter ID laws in other states, she said. "This has all been said before."

At the pro-amendment Minnesota Majority, Dan McGrath was less worried about the language in the bill than with the fact that the Dayton administration -- a vocal opponent of voter ID -- will be charged with defending it.

"I don't have great confidence that [administration officials will] diligently defend it," McGrath said, noting that the Minnesota Majority will be petitioning to join the state as an interested party in defending the amendment. "Voter ID is something that the polls show people want. [Opponents] are afraid of the will of the people. They're afraid to let people vote."

Among the groups joining the ACLU complaint were Common Cause, Jewish Community Action and the League of Women Voters.

Jennifer Brooks • 651-925-5049