Obama and Romney are making one final push through several so-called "battleground" states, where the race between the two candidates remains close. Both delivered final arguments for their respective candidacies Monday in Florida, where early voting over the weekend was marred by long lines and a bomb threat at an Orlando-area polling station.

The candidates were scheduled to hold campaign events less than 10 miles apart Monday evening in the strategically important battleground state of Ohio, whose 18 electoral votes are seen as potentially crucial in determining the winner of the election.