Voters around the nation are set to choose their leaders in Tuesday's midterm election. The selection process varies, but for many voters, party loyalty, incumbents' performance and issues like the Iraq war will play a role.
Thomas Patterson, of Harvard's John F. Kennedy School of Government, says that with most of the electorate, there is no civics-book ideal of comparing candidates before voting.
Patterson says that most people identify with one party and vote along those lines. And it takes a big issue to cause voters to switch their party loyalty, according to Patterson.
A prime example is the Civil Rights movement, which caused some Southern Democrats to become Republicans. Describing a somber mood in the electorate in 2006, Patterson says the U.S. involvement in Iraq could be one of those loyalty-recalibration moments.
Michele Norris talks with Patterson, author of The Vanishing Voter.