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 predi
ctable pattern, as outlined by Carmines and Stimson. Hypotheses: By ap
plying the theory of issue evolution to abortion, I develop three hypo
theses: 1) The reputation for each party's stance on abortion among pa
rty 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 change
s among party elites and masses are causally connected, with elite-lev
el 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 S
urveys, 1972-94. Results: Democrats and Republicans shift dramatically
on the abortion issue at both the elite and mass levels. Moreover, th
is 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.