Charlie Neibergall / AP
Voters stand in line before casting their ballots on the first day of early voting for the November election, Thursday, September 27, 2012, at the Polk County Election Office in Des Moines, Iowa. Iowa is one of 32 states that allow early voting.
Scott Olson / Getty Images
Betty Carlson (L) helps her husband Keith Carlson, who is visually impaired, fill out his ballot during early voting at the Black Hawk County Courthouse on September 27, 2012 in Waterloo, Iowa. In the 2008 election, 36% of voters cast an early ballot in Iowa.
Early in-person voting, an option available in only certain states, opened in Iowa Thursday where lines formed at some polling centers. President Obama currently has an eight point advantage over Mitt Romney in Iowa, according to the latest NBC News-Wall Street Journal poll.
Surveys from the 2008 presidential election showed that early voters favored President Obama over Republican candidate John McCain, but Democrats are not always the favored party of early birds.
Election experts have estimated that as many as 40% of voters will cast their ballot before November 6.