This article explores the dynamics of candidate ambivalence over the course of a presidential campaign. Candidate ambivalence tends to decrease as a campaign unfolds, although the rate of ambivalence decay is not constant across time or individuals. Two alternative theories of ambivalence change are considered and tested. Consistent with a motivational account, the results indicate that partisan reasoning contributes to the diminution of ambivalence over time. Consistent with an informational account, the results suggest that exposure to heterogeneous information heightens ambivalence. Ambivalence is least likely to decline among people who are exposed to cross-cutting information, politically sophisticated individuals with weak partisan attachments, and, during the general election phase of the campaign, those who live in homogenous areas with little political competition.