A perfect storm of voting problems, from machine malfunctions and violence at the polls to dirty tricks and hoaxes, cast a pall over Election Day.
In a number of states, including California, Florida, Illinois, Iowa, Indiana, New Jersey, Ohio, Pennsylvania, Texas and Utah, voters reported that electronic voting machines were not working properly.
Among the errors were voting machines not turning on, failing to scan the ballots, and software that failed to function properly.
Many of these malfunctions were no surprise to election experts who had warned for years that the combination of new technology and high-stakes races would lead to voting fiascos.
"These are problems that anyone who's been paying attention completely predicted," said Tova Andrea Wang, a democracy fellow at the Century Foundation.
"Long lines because there were too few machines -- we saw that in 2004. Improper demands for identification all over the country, instances of voter intimidation -- these are all things that we frankly expected to happen," Wang said.
And some dirty tricks backfired.
A widely circulated voice mail purportedly proving Republican voter intimidation in the bruising Virginia Senate race turned out to be a hoax.
Earlier in the day, after complaints from staffers for Democratic Senate candidate James Webb, the FBI launched a probe into the voice-mail message that informed a voter he would face criminal prosecution if he showed up at the polls.
But Virginia Democratic Party attorney Jay Meyerson contacted Jean Jensen, the executive secretary of the Virginia State Board of Elections, and told her that the voter -- a Clarendon, Va., resident -- "was the victim of a hoax," Jensen told ABC News.
GOP state Chairman Kate Griffin was quick to demand an apology from Webb and fellow Democrats, and accused the party of sinking to "the lowest level" in the campaign.
One state that experienced major problems at the polls this morning was Indiana.
Because of inadequate training of poll workers, about half the precincts in Indianapolis and the rest of Marion County, Ind., had difficulties getting their machines started.
As a result, 175 precincts had to resort to issuing paper ballots, reported The Indianapolis Star.
Because voters in 75 precincts in Delaware County found that the cards to activate the machines had been programmed incorrectly, a judge extended the voting until 8:45 p.m.
Voters who showed up just before noon at a crowded polling place in Denver had to go home because the location ran out of provisional ballots. Two hours later, the ballots still had not appeared.
There were shortages of ballots at other sites in Denver as well, according to Fairvotecolorado.org, a nonpartisan voting education group.
And tiny Daggett County, Utah, had an unusual problem: The county had 947 voters, four times more than its population according to the 2005 Census, according to The Associated Press.
As a result, Attorney General Mark Shurtleff was investigating complaints of vote-stuffing, including claims that the father of a Republican candidate for sheriff had 14 adults registered at his household.
Even candidates had problems voting. In Ohio, Republican Rep. Jean Schmidt, who is locked in a tight race for re-election, was one of the first in line to vote at 6:30 a.m. but the machine rejected her paper ballot. Election officials set it aside to be counted later in the day.
In other states, the problems were more due to human error. A poll worker allegedly choked a voter and pushed him out the door this morning in Louisville, Ky. The unnamed staffer was arrested and charged with assault and interfering with an election, officials said.
A police spokesman wouldn't explain what caused the altercation.
A voter was arrested after smashing an electronic voting machine with a paperweight, damaging its screen, at a polling place in Allentown, Pa.
"He came in here very peaceably and showed his ID, then he got on the machine and just snapped," volunteer Gladys Pezoldt told The Morning Call of Allentown.
In Cincinnati, Republican incumbent Rep. Steve Chabot was turned away from the polls because he failed to bring the proper identification with him. Although poll workers recognized him, Chabot had to go home to get a bank statement that confirmed his home address.
In an election season notable for the nasty tone of the campaign advertising and the brutal tactics to scare voters, the Justice Department has sent out 800 election monitors to 65 cities in 20 states looking for irregularities and evidence of fraud.
Several states, including New Hampshire and Pennsylvania, have set up hot lines where voters can report incidents of fraud or voter intimidation.
In some cases, it may be difficult to apprehend those suspected of illegal voting.
In New York and Ohio, officials are investigating so-called "ghost voters," dead people who are still on the voter rolls -- and who sometimes end up voting.