Close race could delay results as 'provisional' votes may hold key
Americans have just a few more hours to vote for their next president.
The first polling stations Kentucky and Indiana have now closed - but voting will continue in Alaska until around 5am Irish time.
The results are expected to emerge by around 7am tomorrow morning.
However, it could take longer - as the race between President Obama and his Republican challenger Mitt Romney is close.
Opinion polls suggest Barack Obama has edged into a slight lead in the most crucial states.
President Obama's spent election day helping volunteers man phones at his campaign base.
While Republican challenger Mitt Romney made last-ditch stops in Pennsylvania and Ohio.
A special class of ballot called a “provisional vote” could play a key part if the election is extremely close. Provisional ballots are not counted for days or weeks after polling day.
Voters cast provisional ballots for a variety of reasons, including failing to bring ID to the polls, not updating voter registration after moving or trying to vote at the wrong precinct.
A federal election law passed after the 2000 presidential election gives voters the option to cast a provisional ballot, if poll workers deny them a regular one. In Ohio and Pennsylvania, voters who do not take an ID to the polls can still have their votes counted if they produce an ID after Election Day. In Ohio, provisional voters have up to 10 days post-election to produce an ID.
If voters in Florida do not take an ID to the polls, they must sign a provisional ballot envelope. Canvassing boards then will try to match the signatures with those in voter registration records, a process that conjures up images of the 2000 presidential election in Florida.
“It’s a possibility of a complete meltdown for the election,” said Daniel Smith, a political scientist at the University of Florida.