The exceptionally close race between President Barack Obama and Republican Mitt Romney has once again raised the possibility of a candidate winning the popular vote but losing the White House by falling short in electoral votes.In most recent scenarios, Romney is projected as the victim in this quirk of the U.S. voting system.Polls show him winning more overall votes but Obama retaining a narrow lead in enough states to accumulate more than the 270 electoral votes needed to be re-elected.The candidate who wins the most individual votes in a state, even if by just a single vote, almost always gets all its electoral votes."Unless something weird happens in the next couple of weeks, we're going to be talking about very thin margins. And with very thin margins and the particular configuration of the battleground states, I think there is a nontrivial chance we will end up with the outcome of someone winning the popular vote but not the electoral vote," said Alex Keyssar, a professor of history and social policy at Harvard University.If Obama wins the White House with an electoral vote majority while losing the popular vote, it would be the reverse of 12 years ago.That was when agonized Democrats saw Al Gore garner over 500,000 more votes nationally than Republican George W. Bush but lose the electoral vote after the Supreme Court halted a recount in Florida.But the GOP also points to another possibility outlined by political analysts: Romney and Obama ending up tied, with 269 electoral votes apiece, and the election settled by the House of Representatives -- now under the control of Romney's fellow Republicans."A tie is remotely possible but not as likely as a split," Keyssar said. "If a tie happens, Romney is president."