Religious divides in American politics don’t get the kind of attention they used to, but generally speaking, we tend to think of mainline Protestants as being “liberal” in both their theology and in their views on partisan politics. Similarly, Evangelicals are generally assumed to be both traditionalists when it comes to their faith, and hardcore conservatives in their political views. When we look at aggregate numbers for Evangelical Protestants and mainline Protestants, this appears to be true. For this reason it generally makes sense when political scientists include a variable in their model that controls for whether a respondent identifies as an Evangelical. That said, is it true that all mainline Protestants denominations are, on average, liberal Democrats, and Evangelical Protestants are reliable Republican voters? A closer look at each denomination will help us discern the degree to which this is a reasonable expectation.
The 2014 CCES is a useful starting point (I started writing this post before I realized the 2016 CCES was released, and didn’t have the time to recreate the figures with the more recent data; I am confident that little has changed). I first considered the percentage of respondents who identify as Republican, rather than Democratic or independent. I included those that initially identified as independent, but, when pushed, admitted that they leaned toward the Republican Party as being part of the Republican category.
From these figures we see that there is a religious divide between the major mainline Protestant denominations and the major Evangelical denominations, but there are also huge differences within these different Protestant camps. We also see that the idea that mainline Protestants are political liberals and Evangelical Christians are political conservatives is a gross exaggeration. A majority of PCUSA and UMC adherents are Republicans, as are a plurality (and near majority) of ELCA adherents. Even among Episcopalians, we see slightly more Republicans and Democrats. The United Church of Christ was the only mainline Protestant denomination considered here that was majority Democrat, and Democrats were almost a majority among American Baptists. It may be the case that the leadership of these churches leans left on both cultural and economic issues, but when it comes to the actual adherents, it would be incorrect to describe these denominations as overwhelming liberal or Democratic.
Among the Evangelical denominations, we also see great diversity. We see that a majority of respondents who identified with an Adventist denomination identified as Democrats. Although for the other Evangelical denominations, Republicans outnumber Democrats, there is nonetheless a great deal of variation. Southern Baptists, generally considered the backbone of the religious right, are not the most Republican denomination (about 57 percent identified as Republican). Non-denominational Evangelicals and members of the LCMS were each about two-thirds Republican.
One could plausibly argue that the relationship between denomination and politics is really being driven by racial and ethnic differences. That is, these other demographic characteristics are even stronger predictors of political affiliation than religious identity, but religion looks important because it is correlated with these other attributes. Some Evangelical denominations (such as Adventists) are much more racially and ethnically diverse than most mainline Protestant denominations (the ELCA, for example, is overwhelmingly white). Perhaps if we controlled for race and other demographic traits, we would have a better understanding of how religion impacts politics. To consider this question, I created a logit model in which Republican identification was the dependent variable, and specific religious denominations were included as a series of dummy variables; repondents with no religious identity served as the base category. The model controlled for race/ethnicity, age, income quartile, gender, and educational attainment.
The results of this model showed that almost every major Christian group – mainline and Evangelical – were more likely to identify as Republican than the non-religious, even after controlling for these other variables. The only denomination whose difference from the non-religious, in terms of party identification, was not statistically significant was the United Church of Christ. In all others, identifying with that denomination was associated with a greater probability of identifying as Republican.
There were differences of degree, however. Those who identified as an Adventist or an Episcopalian were about twice as likely to identify as a Republican compared to a non-religious respondent. In contrast, those who identified as a non-denominational Evangelical were seven times more likely. We see odds ratio that are almost as impressive for the Southern Baptists, independent Baptists, and the LMCS (all about five times more likely to be Republican than the secular). We also see that, when it comes to partisan politics, Adventists were more similar to mainline denominations than to other Evangelicals; Adventists were only about 1.8 times more likely than the secular to identify as Republican, which was actually a smaller odds ratio than what we see among UMC, ELCA, and Episcopalians, and American Baptists adherents.
So when it comes to politics, the Evangelical vs. mainline distinction has some general value, but it should not be overstated. There is a great deal of variation within these various Protestant families, and some overlap.