There were 13 lawyers filling the courtroom of U.S. District Judge Algenon L. Marbley last week, arguing over a sliver of a slice of the millions of votes that Ohio will count in the 2012 presidential election.

Or, more precisely, those that Ohio plans to not count.

The state’s lawyer, Aaron Epstein, told Marbley that “by any metric,” the number of potentially discarded ballots at issue was too small to warrant intervention by the federal courts.

Marbley was skeptical.

“While we might not look for perfection,” he told Epstein, “if your vote is the vote not being counted, it’s a bad election, agreed?”

Such is the state of play in this Midwestern swing state with a reputation for close elections, messy ballot procedures and litigious politicos. “Will Ohio count your vote?” blared a recent headline in the Cincinnati Enquirer.

Closing the deal with voters is only the beginning for President Obama and Republican challenger Mitt Romney, and not just in Ohio. In courthouses across the country, lawsuits are challenging state laws that dictate who may vote, when they may vote and whether their ballot will be counted once they have voted.

There is a special urgency in the presidential election’s swing states. Lawyers in Colorado are poised to challenge the secretary of state’s proposed purge of noncitizens from voter rolls. A half-dozen suits are aimed at Florida’s raft of voting changes. A Pennsylvania judge is deciding whether a voter ID law there violates the state constitution.

In Ohio, the Obama campaign has filed suit against a law passed by the state’s Republican leadership to shorten the early-voting period.

And the separate issue in Marbley’s courtroom was whether Ohio must count provisional ballots cast in the wrong precinct when the mistake was the fault of a poll worker rather than the voter.

Edward B. Foley, director of the election law center at Ohio State University’s law school, said that because Ohio has been a swing state for so long, voting rights lawsuits have become part of the landscape. Off-year elections serve as training grounds for presidential-year legal battles.

“Each party has enough built-up knowledge and has lawyers that it can go to again and again,” Foley said. “There’s a kind of sophistication to it.”

A familiar battleground

Provisional ballots often are the battleground in Ohio; more than 200,000 such ballots were cast in 2008, more than in any other state besides California.

Such ballots are cast when a voter has some irregularity — a lack of proper ID, a name change not recorded, a missing entry on the voter rolls — that keeps him or her from filing a regular ballot. Local boards of elections then must decide whether to count them.

Some decisions are easy: for instance, if the person filing the ballot is not legally registered to vote.

But the case brought by the civil rights group Advancement Project, the Service Employees International Union and others challenges the part of Ohio state law that says ballots cast in the wrong precinct should not be counted, even if the voter was only following a poll worker’s instructions.

There were 14,000 such votes in the last presidential election, estimates Penda Hair of the Advancement Project. On a constitutional basis, every legitimate vote should count, she said — and on a practical level, “that could be the margin of victory in races from the presidency to the Senate to the House” and lower. Three states in the 2008 presidential race were decided by fewer votes.

Ohio’s voting procedures help create the wrong-precinct problem, said Danielle Leonard, who argued the case before Marbley. Especially in urban areas, several precincts are often grouped together in a single polling place.

Those casting provisional ballots depend on poll workers to make sure they have the proper ballot for their precinct, Leonard said. She referred to it as a voter being in the “right church” but the “wrong pew.”

“At the end of the day, this case is about a state’s responsibility to its voters,” Leonard told Marbley.

In an earlier Ohio case that turned on the counting of such ballots, the outcome of a local election was overturned. The federal judge presiding over the case said that testimony “revealed a chaotic process” in which poll workers had a hard time figuring out which precinct a voter should be in or whether an address was on the even or odd side of a street that provided a precinct boundary.

The challengers said Ohio’s rules about counting provisional ballots violate the equal-protection issues that were at the heart of the Supreme Court’s decision in Bush v. Gore, which stopped additional vote-counting in Florida in the 2000 presidential race.

Defending the law

In an interview, Ohio Secretary of State Jon Husted (R) defended the state’s preparedness and its law, which he helped pass as Ohio’s House speaker.

The state has so many provisional ballots, he said, because it is “bending over backwards” to not turn away voters who seem to lack qualifications.

“We’re trying to give the voter a second chance to cast a ballot and to have that ballot counted,” Husted said. “But in voting, an element of personal responsibility is required. Fundamentally, what this lawsuit is about is whether it’s an individual’s responsibility or the government’s responsibility to make sure you cast your ballot properly.”

The law has been upheld by the Ohio Supreme Court. Husted, elected as secretary of state in 2010, said that he has implemented more-uniform voting procedures across the state, and that this year, all registered voters will receive a card that asks whether they want an absentee ballot, so they may vote “without even leaving their house.”

“What we have in this case is a bunch of California lawyers coming into a federal court to make Ohio law from the federal bench,” Husted said. He was referring to Leonard, whose firm is based in San Francisco.

‘A safety net with a hole in it’

Leonard told Marbley that the state has not put forth “any legitimate reason why these votes should not be counted.” She said her clients were asking the state to count ballots only in races that do not depend on the precinct system, such as for president or secretary of state.

She seemed to have a sympathetic audience. When Epstein called the provisional ballots a “safety net,” Marbley replied: “Don’t give me a safety net with a hole in it.”

Marbley said the question was whether a voter should be disenfranchised because of an election official’s error. “That’s what haunts me, Mr. Epstein,” he said.

The judge promised a quick ruling, acknowledging that whatever he decides will be appealed. He said the goal is to make sure standards are set by Election Day.

Daniel P. Tokaji, another election law expert at Ohio State, said that is a good idea. Imagine a scenario “in which the outcome of the presidential race comes down to Ohio,” he said. “We’ll have a real mess on our hands if we don’t have some standards.”