More than 24 hours after polls closed in Florida, election officials said votes were still being counted in a handful of counties and final results may not be known before the weekend.
"Every county must report their unofficial results to us by Saturday at noon," said Chris Cate, a spokesman for Florida's Secretary of State, who is responsible for elections.
He declined to predict when the race in the fourth most populous US state would be called.
Twelve years ago, when the key battleground state was a toss-up that left the presidential race unsettled, Florida was the cause of electoral gridlock.
This time, it hardly seemed to matter. President Obama handily won re-election without Florida's 29 Electoral College votes, which was the biggest prize up for grabs in any of the US swing states.
As of Wednesday evening, Obama had 49.87pc of the statewide vote versus 49.27pc for Romney, with just 49,963 votes separating them, according to the Florida Division of Elections.
Officials throughout the state blamed an unexpectedly high number of absentee ballots and the length of the ballots, which included 11 proposed state constitutional amendments, for long lines at polling places and delays in tallying final results.
But Republican Governor Rick Scott's decision not to extend early voting ahead of Election Day, after it was cut back from 14 to eight days by Scott and the Republican-controlled Legislature, was also cited as causing exceedingly long voter queues at many precincts on Tuesday.
Democrats have said repeatedly that the cutback was a part of an unsuccessful attempt to blunt turnout in Florida by Obama supporters.
Miami-Dade Mayor Carlos Gimenez apologized for the long lines in his county on Wednesday, after acknowledging that some voters had been forced to wait up to six hours to cast their ballots.
"That should not have happened," said Gimenez, whose county accounts for about 10pc of Florida's nearly 12 million registered voters.
As for the glacially pace of the vote count, Gimenez said: "We had a very long ballot. It was the longest ballot in Florida history."
The final margin of victory in Florida may be less than a percentage point.
Some political pundits say the delays highlight Florida's seeming inability to hold elections that are free of controversy and public mockery.
"There are so many different potential sources of interference and conscious efforts to muck it up, we won't know for a while yet who to point the finger at," said Seth Gordon, a former political consultant based in Miami.
"We could have been there in the bulls-eye of the whole works looking idiotic just like last time," he said, referring to 2000, when George Bush won Florida by 537 and captured the White House.
"We may be just as idiotic this time, but it doesn't matter because no one is watching," Gordon said. "Last time, we held up the entire country."