Issue alignment and partisanship in the American public: Revisiting the 'partisans without constraint' thesis

Prior studies of American polarization suggest that the public gradually sorted themselves into partisan camps in the late 20th century while remaining largely non-ideological. Drawing on more recent data, we reassess these trends and discover a striking increase in the ideological organization of American public opinion in the beginning of the 21st century. Using a broad set of issues from the American National Election Studies, we identify rapid growth in the correlations between political attitudes from 2004 to 2016. This emergence of issue alignment is most pronounced within the economic and civil rights domains, challenging the notion that current "culture wars" are grounded in moral issues. While elite subpopulations show the greatest gains, we find that economic issues become more highly correlated across the electorate. We also find accelerated growth in the association between partisanship and issue attitudes during this period. These findings paint a new picture of the American electorate as not only highly partisan but increasingly ideological.