Politicians routinely appeal to the emotions of voters, a practice critics claim subverts the rational decision making on which democratic processes properly rest. But we know little about how emotional appeals actually influence voting behavior. This study demonstrates, for the first time, that political ads can change the way citizens get involved and make choices simply by using images and music to evoke emotions. Prior research suggests voters behave differently in different emotional states but has not established whether politicians can use campaigns to manipulate emotions and thereby cause changes in political behavior. This article uses two experiments conducted during an actual election to show that: (1) cueing enthusiasm motivates participation and activates existing loyalties; and (2) cueing fear stimulates vigilance, increases reliance on contemporary evaluations, and facilitates persuasion. These results suggest campaigns achieve their goals in part by appealing to emotions, and emotional appeals can promote democratically desirable behavior.