For instance, there’s no more politically unified religious group than Black Protestants, with more than 90 percent of them voting for Mr. Biden in 2020. But while Black Protestants are often supporters of a more liberal approach to economic issues, they are still conservative Christians who oppose many progressive social policies. Over 60 percent of Black Protestants said in 2018 that homosexual sex was always wrong, the same percentage as evangelicals.

At the same time, Democrats must not take for granted the increasing number of atheists and agnostics in their coalition. Atheists provide a particularly difficult problem for Democrats. When asked to place themselves in ideological space, the average atheist sees the Democratic Party as becoming more conservative over the last three years, while they themselves have become more liberal. Data indicates that atheists are the most politically active religious group in the United States in recent years. In a 2018 survey, atheists were twice as likely to donate money or work for a political candidate as white evangelicals. Atheists want the Democratic Party to become more progressive and are unlikely to remain silent if they don’t see changes.

So Democrats have to find ways to pull off a very tricky balance on policy priorities between the concerns of the politically liberal Nones and the more traditional social positions espoused by groups like Black and mainline Protestants.