An often-forgotten passage of Philip Converse's classic essay on mass
belief systems introduced the concept of an issue public - a segment of
voters that has crystallized attitudes about a particular topic. Some
people deeply care about particular topics, and they might be equipped
to reach judgments on these topics. This simple idea could provide an
important corrective to work that casts citizens' political competence
in a negative light. But, previous attempts to evaluate the issue
publics hypothesis have been unsatisfying. This Element proposes and
tests a new measurement approach for identifying issue publics. The
evidence gathered leads to the conclusion that issue publics exist, but
are smaller and more particularistic than existing scholarship presumes
them to be. As such, researchers underappreciate the significance of
issue opinions in electoral politics.