9NEWS political analyst Floyd Ciruli says past surveys have found that five percent of voters don't make a decision until they get into the polling booth.
In a tight race like this, both the Obama and Romney campaigns are expected to keep the rhetoric going until the polls close on Tuesday in an attempt to make the last impression on an undecided voter.
"There used to be a rule that you slow down over the weekend [before the election] and go positive," Ciruli said. "While their stump speeches have gotten slightly positive, you listen, both of them are still putting in zingers right to the end because they're now convinced that you have to keep up the edge right to the end."
Political strategy changed following the 2000 election when Al Gore won the popular vote but George Bush won Florida and the Electoral College.
"From that time on, there absolutely hasn't been a stop in Presidential campaigns until seven o'clock on Tuesday night."
Ciruli says that tactic will keep political advertisements on TV late into the six o'clock hour on Tuesday evening.
(KUSA-TV © 2012 Multimedia Holdings Corporation)