A court denied the group's request for a preliminary injunction in August, and the outcome of the case will now be decided by the commonwealth's highest court. There are currently three Democrats and three Republicans who will hear the voter ID case. If there's a 3-3 decision, the law would stand.
The American Civil Liberties Union of Pennsylvania, the Public Interest Law Center of Philadelphia, the Advancement Project and the law firm Arnold & Porter are handling the group's lawsuit.
Wisconsin officials have asked its highest court to consider a similar measure before the November elections. Two other voter identification cases in Texas and South Carolina were filed under the Voting Rights Act.
"There could be Congressional races or state races where confusion [about proper identification] on Election Day could lead to post-election litigation over the result," University of California Irvine law professor Rick Hasen said.
Ohio Attorney General Mike DeWine and Secretary of State Jon Husted, both Republicans, filed a brief with a federal appeals court Monday, asking it to reconsider a lower court's recent decision to halt changes to the state's early voting rules.
Obama for America in July sued to block a measure passed by the Republican-
controlled Ohio Legislature that ended early voting for most voters during the three days before Election Day. Local election boards were given the leeway to decide whether military and overseas voters could continue to cast in-person absentee ballots. The campaign, the Democratic National Committee and the Ohio Democratic Party said the rules change violated the Equal Protection Clause of the Constitution because it treated groups of voters differently.
Experts say Ohio's early voting case and another in Florida that seems close to being resolved are important because last-minute rules changes can create confusion, including not having the proper ID or having to endure long lines on election day.
"It's a real worry that people who voted early four years ago won't be aware of the fact that the state has restricted early voting this time around," Tokaji said.
In addition to lawsuits brought over voter ID measures and changes to early voting rules, there are challenges to voter purges, technology and provisional ballots winding their way through the courts.
Hasen said if you set aside the larger question of whether these laws and related lawsuits are a good or a bad thing, you're left with the fallout.
"I'm concerned about implementing new rules for the first time on an election day," Hasen said. "You don't write a play and premiere it on Broadway."