OKLAHOMA CITY — It is one of the prime paradoxes of the 2016 election: A twice-divorced candidate who has flaunted his adultery, praised Planned Parenthood and admitted to never asking for God’s forgiveness is the favorite of the Christian right.

The candidate, Donald J. Trump, who won with evangelical voters in South Carolina and has their support in other Bible Belt states that will vote in primaries on Tuesday, has dominated the Republican campaign by appealing to the economically disenfranchised. But the promise of a Trump presidency that would gall the political elites is also resonating with the culturally disenfranchised, including many conservative Christians.

Mr. Trump’s success with evangelicals, who constitute the largest Republican blocs in six Southern states voting on Tuesday, poses a mortal threat to Senator Ted Cruz of Texas, whose campaign is built on these voters. Mr. Cruz will face nearly insurmountable odds if he fails to carry more than his home state on Super Tuesday, with the race afterward moving to less favorable territory.

Mr. Trump’s appeal with the religious right is debunking some long-held maxims about evangelical voters, showing that they are not monolithic; that they do not fall neatly in step with evangelical leaders, many of whom endorsed Mr. Cruz; and that within evangelical ranks lie fault lines of class and culture.