Tuesday marks six weeks until Election Day, but registered voters in two dozen states are already able to cast a ballot for president, with more states to allow early voting in the coming weeks.
In the 2000 presidential election, early voting accounted for 15 percent of the total ballots cast. By 2008, that doubled to 30 percent, according to the United States Elections Project at George Mason University. It's expected to be on the rise again this year.
NPR's Melissa Block spoke with George Mason University professor Michael McDonald on All Things Considered Monday about the rise in early voting. McDonald, who also runs the United States Elections Project, says he expects about 35 percent of voters to cast their ballots early this year — either by mail or in person at a polling place before Nov. 6.
"Voters love this method of voting, and so you tend to see once you open up the spigot of early voting within a state, more and more people start flowing through the election in that way," McDonald says.
In 2008, nearly 80 percent of voters in swing state Colorado cast a ballot before Election Day, McDonald says. Early voting there begins Oct. 15.
"Colorado offers a particular form of early voting that's proven to be very popular in Western states," says McDonald. "[It's] a combination of allowing people to request a mail ballot for any reason whatsoever, and also allowing people to permanently sign up to receive that mail ballot so they just — they sign up once, and they continually receive that mail ballot in future elections."