From the  Washington Post

Much white evangelical support for President Trump is based on a bargain or transaction: political loyalty (and political cover for the president’s moral flaws) in return for protection from a hostile culture. Many evangelicals are fearful that courts and government regulators will increasingly treat their moral and religious convictions as varieties of bigotry. And that this will undermine the ability of religious institutions to maintain their identities and do their work. Such alarm is embedded within a larger anxiety about lost social standing that makes Trump’s promise of a return to “greatness” appealing.

Evangelical concerns may be exaggerated, but they are not imaginary. There are some political progressive who would grant institutional religious liberty only to churches, synagogues and mosques, not to religious schools, religious hospitals and religious charities. Such a cramped view of pluralism amounts to the establishment of secularism, which would undermine the long-standing cooperation of government and religious institutions in tasks such as treating addiction, placing children in adoptive homes, caring for the sick and educating the young.

But this is not, by any reasonable measure, the largest problem evangelicals face. It is, instead, the massive exit from evangelicalism among the young. About 26 percent of Americans 65 and older identify as white evangelical Protestants. Among those ages 18 to 29, the figure is 8 percent. Why this demographic abyss does not cause greater panic — panic concerning the existence of evangelicalism as a major force in the United States — is a mystery and a scandal. With their focus on repeal of the Johnson Amendment and the right to say “Merry Christmas,” some evangelical leaders are tidying up the kitchen while the house burns down around them.  (Michael Gerson, Washington Post, 2019).

I think the answer is, maybe, that young people, regardless of religious outlook, tend to be less racist than the older generation, more tolerant of diversity, deeply concerned about the climate crisis, and also very concerned about their futures in the workplace, the short-term contracts and lack of pay increases over so many years, and so on. This doesn’t make all of them want to vote for Democrats, or to vote at all,  but maybe they no longer share the attitude of their parents towards abortion, women’s rights, minority rights and the environment.   It is also true that religiosity is declining, in the towns and cities at any rate.  America cannot any longer be called a christian nation in any meaningful sense of the word; it started stopping being so a while ago, but its moral corruption gathers at a massive rate, unremarked by old evangelicals.