Recent research has shown that rapid judgments about the personality traits of political candidates, based solely on their appearance, can predict their electoral success. This suggests that voters rely heavily on appearances when choosing which candidate to elect. Here we review this literature and examine the determinants of the relationship between appearance-based trait inferences and voting. We also reanalyze previous data to show that facial competence is a highly robust and specific predictor of political preferences. Finally, we introduce a computer model of face-based competence judgments, which we use to derive some of the facial features associated with these judgments.