Having had more or less sleep changes mood and behavior; for example, more sleep associates with greater productivity and a perception that more time is available. This changes the time cost of voting in ways particularly important for the United States, where the general elections are sometimes but not always held 2 days after a 25-hr day, when people typically have had more time to catch up on sleep. Election returns and surveys confirm that circumstances where the election occurs 2 days after a long day produce higher turnout, suggesting a role for factors that affect sleep in political behavior.