President Obama has announced he will travel back to his adopted hometown of Chicago to vote early on October 25. This will be the first time a presidential candidate has not voted in person on Election Day. Michelle Obama voted absentee a few days ago.

Michelle Obama has referred to early voting as the Obama campaign’s “secret weapon,” and it certainly has been in the past. In 2008, 30 percent of all votes were cast via early voting–an increase of 10 percentage points from 2004, when 20 percent of ballots were cast in this way. early voting ballots favored Obama and it appears that 2012 will produce an early voting turnout that is even higher.

In a Talking Points Memo piece on early voting, George Mason Professor Michael McDonald estimated that the election will be won or lost before Election Day:

I am forecasting in this election cycle that about 35 percent of the vote will be cast before Election Day. We know 78 percent of all votes in Colorado were cast prior to Election Day in 2008, and it probably will be around 85 percent in 2012. The election will essentially be won or lost before Election Day unless it’s a tight, narrow, razor-thin margin.

42 states allow early voting either by mail or in-person, while 33 of those allow it without an “excuse,” according to Ballotpedia:

Image courtesy of Ballotpedia.org

Democrats are fiercely attached to early voting; any attempts to question either its constitutionality or susceptibility to voter fraud are met with claims of racism and voter suppression. A decision earlier this month by the federal appeals court directed Ohio as to how they would run their elections, allowing for expanded in-person early voting that the Ohio secretary of state had removed. Ohio’s secretary of state has said he will appeal to the Supreme Court.