But we're getting ahead of ourselves. People throw around terms, such as "evangelical" and "charismatic," as if everyone agrees as to what they mean, but scholars, who spend most of their time thinking about such things, don't even agree. Plus, how they are captured on one survey can differ substantially from how they are on another. Thus, before continuing this exploration of why so many white Christians voted for Trump, we need to define a few terms first.
Probably the most widely-used classification scheme of religious traditions is the one outlined by Brian Steensland, Jerry Z. Park, Mark D. Regnerus, Lynn R. Robinson, W. Bradford Wilcox and Robert D. Woodberry in their 2000 Social Forces article, "The Measure of American Religion: Toward Improving the State-of-the-Art." Popularly known as "RELTRAD" (religious tradition), this scheme sorts people into 7 broad groups: Evangelical Protestant, Mainline Protestant, Black Protestant, Roman Catholic, Jewish, other religious groups, and no religion. The sorting is usually accomplished through a series of questions about the survey respondents' religious affiliation.
Although the RELTRAD classification is quite good, it isn't perfect. Take Mainline Protestants for instance. Mainline Protestants are those who attend some of the more historic denominations in the United States: the United Church of Christ (Congregational), the Episcopal Church, the Presbyterian Church USA, the United Methodist Church, Disciples of Christ, American (Northern) Baptist Churches USA, and the Evangelical Lutheran Church of America. Some count the Quakers and the Reformed Church of America as part of the mainline as well. However, although Mainline Protestants are, on average, theologically more liberal than Evangelical Protestants, there's plenty of individuals who identify as evangelical but belong to a Mainline denomination. For example, the United Methodist Church is in the midst of a split among its more conservative (i.e., evangelical) members and it more liberal ones.
The Black Protestant category includes historical Black Church denominations, such as African Methodist Episcopal Church and the National Baptist Convention, along with a number of younger Pentecostal churches, such as the Church of God in Christ and the Pentecostal Assemblies of the World. In other words, they hardly represent a monolithic block and could easily be sorted into a number of subcategories much like Evangelical Protestants. Adding to the confusion is that some Black Protestant churches dually-align with Mainline Protestants. For example, a number of Progressive National Baptist churches (a denomination founded by the Rev. Martin Luther King, Jr. in 1961) also belong to the American Baptist Churches USA.
And then there are the Roman Catholics. Although sorting respondents into this category is relatively straightforward, it ignores the diversity of Roman Catholicism. It runs the gamut from theologically conservative to theologically liberal, and it has its own Pentecostal Christians although they're typically referred to as "charismatic."
And then there are some Christian groups, such as Eastern Orthodox, who are quite similar to Roman Catholics, but because they constitute such a small percentage of the American population, they're sorted into the "other" category, which interestingly also includes Buddhists, Hindus, Mormons, and more (Note: some scholars consider Mormons to be a branch of Christianity, while others do not).
Finally, let's consider Evangelical Protestants. Ideally, this category should be broken down into three subcategories: Fundamentalist, Evangelical, and Pentecostal. As Christian Smith noted in his 1998 study of American Evangelicalism, Fundamentalists tend to be more theologically conservative than Evangelicals and are more likely to maintain a "distance" between themselves and secular society. Evangelicals, by contrast, tend to engage the secular world and, as such, more civically and politically active. Pentecostals share many beliefs with Fundamentalists and Evangelicals, but they also believe that the Holy Spirit can move in and through people, leading them to speak in tongues, which can be seen as a form of divine revelation. Moreover, because they believe that the Spirit manifests itself in both women and men, unlike Fundamentalist and Evangelical denominations, Pentecostal denominations (e.g., Assemblies of God, Four-Square Gospel) have been at the forefront of ordaining women. It is among Pentecostals that we will find the charismatic "prophecy voters" mentioned earlier. That is, they are a subset of a subset of Evangelical Protestantism.
Where, then, will we find the white evangelical Christians who voted for Donald Trump? Most will be found within the traditional Evangelical Protestant denominations, but you'll also find them among Mainline Protestants. And there may be even a few Catholics, Eastern-Orthodox, and Mormons who might self-identify as evangelicals. Finally, there are a number of multi-ethnic congregations that are supposedly "white" Evangelical Protestant churches, and there are plenty of Black Protestant congregations that attract their share of white evangelicals.
In short, who "counts" as a white evangelical is hardly straightforward, suggesting that although there's little doubt that conservative Protestants voted overwhelmingly for Trump, we should take the 81% stat with a grain of salt.