[영문]Cognitive dissonance theory predicts that the act of voting for a candidate leads to a more favorable opinion of the candidate in the future. We find support for the empirical relevance of cognitive dissonance to political attitudes. We examine the presidential opinion ratings of voting-age eligibles and ineligibles two years after the president's election. We find that eligibles show two to three times greater polarization of opinions than comparable ineligibles. We find smaller effects when we compare polarization in opinions of senators elected during high turnout presidential campaign years with senators elected during nonpresidential campaign years