TRENDS: Diploma divide: Educational attainment and the realignment of the American electorate

Abstract

The divide between college graduates and non-college graduates is an increasingly important political cleavage. In this paper, I document the rise of the diploma divide on the micro and macro levels. First, I use ANES and CES data to assess the relationships between educational attainment, partisanship, and vote choice. I find that post-2000, educational attainment is an increasingly strong predictor of partisanship and, in turn, vote choice. I demonstrate that differences in racial and culture war attitudes between college graduates and non-graduates drive the diploma divide. I then show that the increasing salience of education at the individual level has reshaped the macro-level political alignment. Between 2000 and 2020, the percentage of a county’s population with a BA is one of the strongest predictors of changes in vote share, with highly educated counties becoming more Democratic and less educated counties becoming more Republican. Finally, I demonstrate that county-level educational context conditions the effect of degree-holding on individual-level behavior. Having a college education is a stronger predictor of Democratic partisanship in counties where a larger proportion of the population holds a college degree. Overall, these results demonstrate the diploma divide is one of the dominant political cleavages in contemporary American politics.