Voters prefer political candidates who are currently in office (incumbents) over new candidates (challengers). Using the premise of query theory (Johnson, Häubl, & Keinan, 2007), we clarify the underlying cognitive mechanisms by testing if memory retrieval sequences affect political decision making. Consistent with predictions, Experiment 1 (N = 256) replicated the incumbency advantage and showed that participants tended to first query information about the incumbent. Experiment 2 (N = 427) showed that experimentally manipulating participants’ query order altered the strength of the incumbency advantage. Experiment 3 (N = 713) replicated Experiment 1 and, in additional experimental conditions, showed that the effects of incumbency can be overridden by more valid cues, like the candidates’ ideology. Participants queried information about ideologically similar candidates earlier and also preferred these ideologically similar candidates. This is initial evidence for a cognitive, memory-retrieval process underling the incumbency advantage and political decision making.