Ohio: "The polls shall be kept open until such waiting voters have voted."
But one tightly contested battleground state, Indiana, has an unusual "chute system" written into its code: "The inspector shall require all voters who have not yet passed the challengers to line up in a single file within the chute." The "chute" is defined as the "area or pathway that extends fifty feet in length, measured from the entrance to the polls."
According to county officials, the chute is more of a metaphysical concept than any defined boundary, and some state officials say they worry that it will be open to interpretation on Election Day.
In Marion County, Indiana, home of the state's capitol, the staff of the election board has expressed worries that some voters, media and political parties may hold "different views regarding the law."
Last week, Indiana Secretary of State Todd Rokita issued guidelines to county election officials. "It is my opinion that an eligible voter who arrives at a poll location prior to the 6 pm deadline should be allowed to vote," he wrote in a memo, but he left it up to the "common sense" of the inspector to determine whether voters have arrived on location.
State Democrat officials say his guidance doesn't go far enough.
"He's been talking about a record turnout in Indiana and has not done due diligence to prepare for it" Indiana Democrats spokeswoman Lauren Smith said. She said that there is no legal definition of how wide the chute can be and whether some officials could create chaos by attempting to organize voters by snaking the line inside the chute to keep it within the 50-foot length.
Indiana, a tight battleground state, will host last-minute visits from both presidential candidates, eager to shore up their support there.
In close races, lawyers working for Democratic candidates have typically worked to make sure that all those in line at closing time have the opportunity to cast their ballots and Republicans have generally watched to ensure that no one who arrives in the line after polls close is allowed to vote.
But the issue doesn't always break down along party lines.
"It's likely we will see this play out in urban areas, but I think it is not inconceivable that in some pocket of places favorable to the Republicans the roles could be reversed," Foley said
Party lawyers will make strategic calculations if it is worth going to state or federal court to ask for an extension of polling hours on Election Day.
"One of the reasons a court might order extended hours could be long lines," Pitts said. "But another, probably more common, reason for extended polling hours will be some sort of malfunction on Election Day like, for example, problems with the voting machines."
If the polling hours are extended by court order, federal law requires all persons who cast ballots after regular hours to vote on a provisional ballot. These ballots will not be treated as a standard ballot. They will be vulnerable to challenge and will be counted after Election Day.
"These votes are set aside for the purpose of deciding whether or not court-ordered extension was lawful," Foley said.
A court order extending the polling hours could, therefore, lead to more details, and more burden on the voter, who will, depending on the state, have to fill out more lengthy paperwork associated with the provisional ballot.
ABC News' Theresa Cook contributed to this report.