The book's author, Janelle Wong, details for The Washington Post how her research led her to that conclusion. She teamed up with other social scientists from the University of California at Los Angeles, Baylor University and Arizona State University to conduct a nationwide public opinion study online a few months after the 2016 election.
Their research showed how much white evangelicals differ from not only the overall population, but from other whites and other evangelicals. Election Day exit polls showed that 80 percent of white evangelicals voted for Trump, while 59 percent of non-evangelical whites voted for Clinton. Part of that discrepancy is because white evangelicals are more conservative on many issues, even more so than Latinx, Asian American and black evangelicals.
At the same time, white evangelicals are declining as a proportion of the population; almost all evangelical growth comes from Latinx and Asian Americans--and that's making white evangelicals nervous, Wong writes. Some pundits have conjectured that economic anxiety is the main reason for evangelicals' support of Trump, but Wong's research doesn't bear that out. Instead, her team's research found that "white evangelicals’ perceptions they’re the targets of discrimination – more so than other groups" was at the heart of evangelical votes for Trump, she writes, and predicts, "The racial fears and anxieties that underlie their support for the president will probably remain the driver in their political views long after he leaves office."