Turnout in Tuesday’s presidential election will probably fall below the levels of 2008 and 2004 based on voter registration trends, according to a longtime analyst of American voting behavior.

Curtis Gans, director of the Center for the Study of the American Electorate, estimated that 56 percent to 58 percent of eligible citizens will vote this year, down from 62.3 percent in 2008 and 60.6 percent in 2004.