(CNN) -- A day before Tuesday's election, millions of people in key states have already cast absentee or early ballots despite long lines, legal disputes over poll procedures and damage inflicted by Superstorm Sandy.
In Ohio, which may be the decisive battleground state, the deadline for early voting passed Monday afternoon. By Friday, more than 1.6 million of Ohio's 7.9 million registered voters had cast ballots, either in person or by mail, said Matt McClellan, a spokesman for Ohio Secretary of State Jon Husted. About 200,000 of the 1.3 million absentee ballots that had been distributed were still out, he said.
Election officials are already facing a lawsuit over how provisional ballots -- issued to people whose eligibility to vote at a particular precinct was in question, or if they requested an absentee ballot but didn't return one -- should be filled out.
State law says poll workers need to note a voter's drivers' license number or the last four digits of a Social Security number on the ballot. But left-leaning groups say instructions Husted issued to election officials on Friday appear to indicate that writing down those digits is the voter's job, not the poll worker's, and warn that could result in votes being thrown out when provisional ballots are counted November 17.
The state has until Tuesday to respond to the request. But Husted, a Republican, said on Sunday that the process "is consistent with the courts and consistent with the law."
"We believe that this is the best way to make elections run successfully so that the most votes are counted," he said. "We believe it's consistent with the law. We believe it's the right way to run elections in Ohio."
Husted had already been taken to court for trying to cut off early voting in the three days before Tuesday, with Democrats accusing him of trying to suppress the votes of Democratic-leaning constituencies. Husted called that "an absurd notion."
"The rules are the same for everybody," he said. "They don't target any one group or individual. What we're trying to do is to make the system run fair and smooth for everybody."
Other eyes were on Florida, another vote-rich state where polls show President Barack Obama and former Massachusetts Gov. Mitt Romney running neck-and-neck.
There were still long lines for early voting when the deadline passed over the weekend, so election officials in the state's most populous belt -- Palm Beach, Broward and Miami-Dade counties -- allowed voters to pick up, fill out and submit absentee ballots. In Miami, the lines snaked around the block from the office of the county supervisor of elections ahead of a Monday afternoon deadline.
State Republicans, led by Gov. Rick Scott, had pushed to cut the number of days available for early voting from 14 to eight. Democrats went to court to get that period extended, arguing the polling facilities in south Florida, a Democratic stronghold, weren't up to the demand.
In the Northeast, the states hit hardest by Superstorm Sandy were trying to make accommodations for people who had been displaced by the storm or whose normal poling places had been knocked out of commission.
In New York, voters in some counties may get an extra day to cast ballots if the disruptions prevent enough citizens from showing up, state Board of Elections spokesman Thomas Connolly said Sunday.
County election officials could ask to allow another day of voting if Tuesday's turnout is less than 25%, he said. The state board would consider the request and, if approved, a second day of voting would be scheduled within 20 days of Tuesday, he said.
Polls would be open for 11 hours on the second day, with only those who were eligible to vote on Tuesday allowed to cast ballots. Nassau County Elections Commissioner William Biamonte expects a "significant drop-off" in the turnout on Long Island, which saw extensive flooding when the storm hit October 29.
In New Jersey, where Sandy made landfall, residents displaced by the storm will be allowed to vote by e-mail or fax, the first time civilians have been allowed to cast ballots remotely.
In many states, remote electronic voting is already available to members of the military and U.S. citizens living overseas. New Jersey's announcement allows people who have been forced to leave their communities, as well as emergency workers working with disaster-relief efforts away from home, to do the same.
The presidential race isn't expected to be close in New York or New Jersey, both longtime Democratic strongholds in national politics. But experts have raised concerns about the security of electronic voting in the past, and New Jersey officials did not explain how they will authenticate e-mails or faxes from voters.
CLICK HERE for additional presidential election coverage via FOX6Now.com.