Other people will have to cast provisional ballots — those who have changed their names or moved but not sent in a change of address, or those who have registered just prior to the deadline this year but whose names don’t show up on local precinct lists. There will also be people trying to vote who aren’t eligible — because they didn’t register in time or don’t have even a non-photo form of ID. By law, none of those provisional ballots can be opened and counted for ten days — until November 17. Voters have those ten days to contact their local election board to provide additional information to get their vote counted. In addition to provisional ballots, some 20,000 or more absentee votes that arrive after Election Day will remain uncounted for ten days.

“Ohio could be close enough that those provisional and other ballots will matter,” says Tom Burke, the chairman of the Board of Elections in Hamilton County, which contain’s Cincinnati. In 2008, over 207,000 such ballots were cast. Ohio has often been close in presidential contests. Jimmy Carter won the state by only 11,000 votes out of 4.1 million cast in 1976, and in 2004 George W. Bush’s margin of victory was only 119,000. Lawyers for John Kerry, Bush’s opponent, have told me they planned to go to court in Ohio if the margin had been less than 50,000 votes. Kerry did not concede the state — and the presidency — until 11 a.m. on the Wednesday after the election.