Subjective agreement between voters and the party they voted for can be produced by three separate processes: rational selection of parties, persuasion by parties, and distortion of perceptions. Rational choice theory, balance theory and social judgment theory make different predictions about the strength of each of these processes. In this article the strength of the three processes are estimated by modeling continuous longitudinal change in attitudes and perceptions of positions on nuclear energy in a period in 1986 during which the accident at Chernobyl occurred. The study uses a short-term panel study of Dutch respondents covering this period. The analyses demonstrate that changes in attitudes and perceptions conform largely to the Downsian model of democracy. Evidence is found for a weak persuasion effect, but hardly any distortion of perceptions occurred. These findings challenge the applicability of concepts from balance theory to the field of electoral research. It is argued that voters have little psychological motivation to distort their perceptions of party positions because they are normally not strongly involved with politics or political parties.