ST. PAUL, Minn. (AP) — Former Democratic Vice President Walter Mondale and former Republican Gov. Arne Carlson became the public faces Tuesday of a fight against a proposed Minnesota constitutional amendment requiring voters to present photo IDs at the polls.

The pair was introduced as two of four co-chairs of the Our Vote Our Future coalition’s campaign against the ballot measure. Voters will decide in November whether to make government-issued photo identification essential to participating in an election.

The coalition’s advisory committee is decidedly heavy with former Democratic officeholders.

This spring, the Republican-controlled Legislature advanced the measure to the ballot without the support of any Democratic lawmakers. Constitutional amendments don’t go before the governor, so Democratic Gov. Mark Dayton had no chance to stop a proposal he opposed. A lawsuit aiming to keep the amendment off the ballot is pending.

Supporters argue the proposed amendment is a guard against voter fraud. Minnesota is among an increasing crop of states where photo ID measures are pending or are now in place.

Mondale said at Tuesday’s news conference that he believes the requirement is intended to discourage voting.

And Carlson said he thinks moderate Republicans will turn against the proposed amendment when they delve into the uncertainties over implementation costs and logistics, such as preserving easy access to absentee balloting and creating a backstop for voters who lack the proper ID cards.

“Frankly, it terrifies me,” Carlson said.

It’s not clear what precise role the big-name leaders will play in the campaign, but Carlson said he expects to travel the state to meet with newspaper editorial boards and would be willing to participate in campaign-style debates.

Meanwhile, Minnesota Secretary of State Mark Ritchie urged the state Supreme Court to act quickly on the lawsuit challenging the ballot question as misleading. The court is due to hear arguments in mid-July. Ritchie said in a letter to the chief justice that a decision before Aug. 21 “would be ideal” so ballots can be printed in time. He said a decision is needed by Aug. 27.

Elections Director Gary Poser said in an attached affidavit that many county auditors hope to design and start printing their general election ballots — which include proposed constitutional amendments — within two weeks of the Aug. 14 primary. The quick turnaround is necessary, Poser said, because absentee ballots must be made available by Sept. 21.

If the court rules too late that the amendment is invalid, voters could still see the question on their ballots. Local election officials could be ordered not to count the votes under that scenario, Poser said.

(© Copyright 2012 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)