Abortion: Evidence of an issue evolution

Theory: Using Carmines and Stimson's issue evolution model of partisan change, I argue that the abortion issue has transformed the two major United States political parties and that this process follows a predictable pattern, as outlined by Carmines and Stimson. Hypotheses: By applying the theory of issue evolution to abortion, I develop three hypotheses: 1) The reputation for each party's stance on abortion among party elites has grown clearer and more distinct over the last 20 years; 2) At the mass level, people have changed their party identification in a manner consistent with their attitudes on abortion; 3) The changes among party elites and masses are causally connected, with elite-level changes producing mass-level responses. Methods: Simple time series analyses are used on two datasets, roll call votes on abortion in the United States Congress and public opinion polls from General Social Surveys, 1972-94. Results: Democrats and Republicans shift dramatically on the abortion issue at both the elite and mass levels. Moreover, this change closely follows with the issue evolution model. The process unfolds gradually, and causality appears to run from elites to masses, rather than from masses to elites.