Cal Clark & Janet Clark 
Women at the Polls [PDF ebook] 
The Gender Gap, Cultural Politics, and Contested Constituencies in the United States

Since 1980, most elections in the United States have been marked by a "gender gap" in which women are more supportive of Democratic candidates than men by nearly ten percentage points. Women at the Polls finds that this gender gap is quite extensive as it exists in almost all demographic groups and as it is based on similar differences in the political attitudes of women and men over a wide array of issues. This suggests that women are becoming an important constituency in U.S. politics.