Political analysts say the results of some close elections across the United States could be delayed for days or weeks, as absentee and provisional ballots are counted.
Many states have allowed voters to cast absentee ballots for weeks. Those votes, however, usually take longer to count, and a final tally of the results from those ballots could take days.
Provisional ballots are often used when a voter is not registered at the polling place, who did not bring the proper type of identification or who shows up at the wrong voting precinct.
In 2004, the first year provisional ballots were used nationwide, about 1.9 million people cast them. More than 1.2 million of those votes were ruled valid.
In the northwestern state of Washington in 2004, provisional ballots played a role in delaying Democratic gubernatorial candidate Christine Gregoire's victory for more than eight weeks.