We examine 'heuristic' and 'systematic' candidate-appraisal strategies within a presidential election context. Controlling for political knowledge, we determine whether individual differences in the capacity for ideological thought condition voters' reliance on the major determinants of candidate choice, increasing reliance on policy considerations and decreasing reliance on the heuristic cue of party identification and on perceptions of candidate character when ideological capacity is high, and exerting the opposite effect - decreasing the role of issues and increasing the role of party identification and candidate qualities - when such capacity is low. Using American National Election Studies data from the 1984-2000 period, we find that ideological thinking consistently heightens voters' reliance on issues and decreases their reliance on candidate cues, but only among voters who report being concerned about the outcome of the election. In contrast, the effect of partisanship is stable across levels of ideological thinking and concern about the campaign. We discuss the cognitive processes by which ideological thinking regulates political choice, and assert its centrality in the political decision-making process.