This article explores the roots of America's partisan gender gap, showing how ideological party sorting created this divide. The emergence of male Republican and female Democratic leanings stems from two major shifts: growing elite polarization between parties, and public awareness matching these differences.

The core mechanism is straightforward: stable policy preferences between genders aligned with increasingly distinct party ideologies. Crucially, education plays a role in making people aware of this sorting process. Those with higher education developed the partisan gender gap earlier because they became attuned to ideological distinctions more quickly.

Using decades of American National Election Studies data and a newly compiled Gallup survey dataset tracking individual responses over time, the study provides strong evidence for its explanation. This combination confirms both the historical development and persistence of the modern US partisan gender gap.