The differences between the two coalitions start with gender. According to Gallup, Republicans split between 52.5 percent male and 47.5 percent female; Democrats are 55 percent female and just 45 percent male. Democrats are slightly younger and more concentrated in the East (24 percent of Democrats live there, compared to 19 percent of Republicans) while Republicans tilt toward Dixie (Southerners represent 36 percent of Republicans compared to 31 percent of Democrats.)
Democrats are still slightly more downscale than Republicans: 72 percent of Democrats report earning ess than $90,000 annually compared to 66 percent of Republicans. But the evolving class nature of the two parties' coalitions is evident in their convergence on another measure: the share of Democrats and Republicans with and without college degrees is now almost exactly the same.
The bigger differences between the parties come on four other dimensions. The first is race. The GOP remains a preponderantly white party: nearly 87 percent of Republicans are white. Just 63 percent of self-identified Democrats are white. African-Americans and Hispanic combine to provide 33 percent of the Democratic coalition, but just 10 percent of the Republican base.
The second key difference is religious affiliation and practice. Republicans are considerably more likely than Democrats to describe religion as important in their lives (73 percent of Republicans do so, compared to 59 percent of Democrats), and to attend church regularly (40 percent of Republicans say they attend at least weekly, compared to only 27 percent of Democrats.) The GOP is also more heavily tilted toward Protestants: three-fifths of Republicans identify with that faith, compared to only 48 percent of Democrats. (The data Gallup released doesn't differentiate between Mainline and evangelical Protestants, but other studies show the GOP evolving increasingly toward the latter over recent decades.) Strikingly, almost one-in-five Democrats now identify with no religious faith, compared with less than one-in-ten Republicans.
The third sharp difference is marital status: 62 percent of Republicans are married while 54 percent of Democrats are single.
Finally, the parties are sharply divided by ideology. Continuing a generation-long process that I've described as "the great sorting out," each party is more ideologically consistent than it once was - but the process is far more pronounced among Republicans. Fully 68 percent of Republicans identify as conservatives compared to 26 percent as moderates and only 6 percent as liberals. Among Democrats, 37 percent consider themselves liberals, while 42 percent identify as moderates and 20 percent as conservatives.
These differences underscore not only the distance between the parties, but their contrasting internal profiles. Across these key measures, Republicans coalesce much more dramatically than Democrats: whites, Protestants, married people, those who consider religion a priority, and conservatives all constitute a larger proportion of the Republican coalition than their opposites do inside the Democratic coalition. In all those different ways the GOP coalition is more homogenous and unified; the share of Republicans who consider themselves conservatives is much larger, for instance, than the share of Democrats who identify as liberals. These data make clear that Republicans have a central archetype: married whites who consider themselves conservative and view religion as important in their lives. No single group is nearly as dominant among Democrats. (Not even single, secular, liberal minorities.)