Electoral College map
Electoral College mapAFP Photo

Americans go to the polls in 30 hours on Tuesday in what has been arguably the bitterest and nastiest presidential campaign in history.

Virtually all polls show a virtual tie, but they give President Barack Obama an edge in the all-important electoral college vote, although the gap is far from being enough for a sure victory.

One of the most important factors will be the actual voting turnout. Polls have consistently showed that Obama has more support from registered voters than he does from those likely to vote.

A CNN poll shows both candidates in a virtual tie. A Wall Street Journal/NBC News/Marist poll survey shows Obama with a razor-thin one point edge, which worked out to a statistical tie when taking into account the poll’s margin of error.

The latest ABC News/Washington Post survey showed the race tied, with both Obama and Romney receiving 48-percent support among likely voters.

Both President Obama and Romney appealed to swing state voters Sunday for the decisive edge they both know is needed to win, AFP reported.

Romney's efforts included a surprise foray into Pennsylvania, a Democratic-leaning state that Republican strategists say is breaking his way. One state poll last month showed a  surprising edge for Romney, but most surveys give Obama a lead.

Pennsylvania has been in Obama's column for months, with the latest Real Clear Politics average of polls showing the incumbent up 4.1 percentage points in a state he won handily, by more than 10 percent, in 2008.

The Obama campaign was not impressed by Romney’s efforts in the “Keystone State". "We're taking back the White House because we're going to win Pennsylvania," Romney told a crowd put at around 30,000, according to U.S. Secret Service estimates quoted by the campaign, who had gathered on a farm in frigid weather.

After his first event of the day in Des Moines, Iowa, the Republican flew to Cleveland, Ohio, firing up the crowd with loaded questions about Obama policy -- all met, by design, with shouts of "No" from the assembled party faithful.

"If the president were re-elected, he would..." Romney began later in his stump speech only to be interrupted by another huge "Nooooo!" in support. "It's possible, but not likely," replied Romney in a rare, unscripted moment.

Obama is counting on Ohio workers’ in the huge automotive industry to give him enough support to win the key state.

On a grueling swing, the Democratic incumbent traveled to Florida and then Ohio, and was set afterward to visit Colorado before touching down in Wisconsin in the early hours of Monday.

The electoral college vote could end up in a tie, leaving the technical but unlikely possibility of the Republican-controlled House of Representatives exercising its constitutional power to decide who will be the president. In that case, it would give Romney the nod while the Democratic-controlled Senate, which in the event of a tie decides who will be the vice president, conceivably could vote for Joe Biden.

However, most analysts say a tie in unlikely, and if there is one, the Senate likely would bow to reality and vote for Paul Ryan.

Michael Luciano, wrote on Policy Mic.com that his projection of the final electoral college vote is 290 for Obama and 248 for Romney.

“Even if Romney were to win Ohio, in addition to Florida and Virginia, he would need to snag one other state currently in blue. That is a tall order,” he wrote. “Control of the U.S. Senate and House is also at stake. Currently the Democrats enjoy a 53 to 47 seat lead in the upper chamber, and current polling indicates that the Republicans are likely to remain in the minority.