And it's a big "IF", But here are Gallup’s stats from October 28, 2008: Obama led in early voting by 15 points (55/40). His election day edge was just three points. He ended up winning by seven points. One more note. According to Gallup, by 10/28/08, the percentage of Americans who said they’d already voted or planned to vote early was 33 percent. Four years later, that number sits at…33 percent.
Today, Romney currently leads Obama 52% to 45% among voters who say they have already cast their ballots. However, that is comparable to Romney's 51% to 46% lead among all likely voters in Gallup's Oct. 22-28 tracking polling. At the same time, the race is tied at 49% among those who have not yet voted but still intend to vote early, suggesting these voters could cause the race to tighten. However, Romney leads 51% to 45% among the much larger group of voters who plan to vote on Election Day, Nov. 6.
If these numbers are even close to accurate - and Gallup's presidential track record is solid - then Romney will take the national popular vote by roughly 4% - and with it an electoral college majority.