Whether someone is single or married ?remains one of the most reliable predictors of party identification among major demographic variables? in the United States, according to polling from Gallup.

The analysis finds:

The percentage of all Americans who identified as Republican in June was 28%, but is higher at 33% among those who are married, and a lower 21% among unmarried Americans. On the other hand, Democratic identification in June was at 35% overall, but 31% among married Americans, and 41% among those who are not married. This marriage gap in party identification is evident across races as well as age groups.

Gallup found that Americans living in a domestic partnership and those who are single/never married, separated, or divorced tend to prefer Democrats. Married whites tend to prefer Republicans.

Some possible reasons for the disparity:

Marriage is a predictor of conservative ideology and conservative positions on social issues, which in turn predict high levels of Republican identification. Being unmarried is a predictor of more liberal ideology and more liberal positions on social issues, which predict higher levels of Democratic identification. Marriage is also associated with religious intensity, including church attendance and importance of religion in one’s life. These measures of religion, in turn, are important predictors of party identification. But it is uncertain whether religion, ideology, and party lead to choice of marital status, or whether marital status leads Americans to different ideological, religious, and partisan choices.