What happens if Barack Obama and Mitt Romney tie for electoral votes?

KANSAS CITY, Mo. - Election-eve polls indicate that the race for President of the United States is almost a dead heat, raising questions about what will happen if neither Barack Obama nor Mitt Romney get the required 270 Electoral College votes needed to win.

The Electoral College is a group of 538 people called electors -- typically party leaders -- in each state, who choose the president based on the popular vote in their state. A presidential candidate needs 270 electoral votes to win.

Each state is granted one presidential elector for every member of Congress: One for each member of the House of Representatives, where seats are allocated according to population, and two more because each state has two senators. That guarantees each state will have at least three electoral votes.

Look at possible ways for each candidate to get to 270: www.270towin.com

Missouri has 10 electoral votes, and Kansas has six.

In most states, the popular vote winner captures all of that state's electors. The only exceptions are Nebraska and Maine, which award electors proportionally.

The Electoral College system can produce two anomalies.

As happened to then-Vice President Al Gore, who lost to George W. Bush in 2000, a candidate can win the popular vote but lose the presidency.

RELATED | Past electoral college-popular vote splits: http://bit.ly/VQsQ0J

Or candidates can tie for electoral votes, 269 each, which throws the tie-breaking decision into the House of Representatives. The choice of vice president falls to the Senate.

"Each delegation from each state in the house gets one vote," said Dr. Beth Miller, assistant professor of Political Science at the University of Missouri - Kansas City.

With the House expected to remain in Republican hands, a tie would mean a Romney presidency. Democrats are likely to retain control of the Senate, meaning Vice President Joe Biden would have a second term.

Miller explained that a tie in the Electoral College hasn't happened since the presidential election in 1828, in which John Quincy Adams became president.

"I do not think there will be a tie this year in the Electoral College," Miller added.

But the political science expert said that with polls all over the map showing each candidate winning battle ground states, anything could happen.

"The polls show what eligible voters will do," she said. "The question is, will those eligible voters cast their ballots? So voter turnout is key in this election," Miller concluded.

The Associated Press contributed to this report.