A comprehensive literature relates voters' electoral decisions to their perceptions of candidates' personalities. Yet the mechanisms through which voters are attracted to certain candidates and not to others remain largely unresolved. To answer this question, this article integrates two recent interdisciplinary insights. First, leader and candidate preferences are found to be strongly dependent on levels of contextual conflict. Second, individual differences in political ideology are shown to be rooted in fundamental psychological orientations leading conservatives and liberals to perceive society in fundamentally different ways: Conservatives tend to perceive the social world as dangerous and threatening, whereas liberals to a larger degree see society as a safe place characterized by cooperation. Based on this, it is predicted that conservatives and liberals will also prefer different candidate personalities. Specifically, conservatives are predicted to value candidate power and "strong leadership" more than liberals, whereas liberals are predicted to value candidate warmth more than conservatives. The prediction is supported observationally using the 1984-2008 American National Election Studies and experimentally in two original experiments conducted in the United States and Denmark. Consequences and scope conditions for trait-based voting are discussed.