"Why did American evangelicals surrender so quickly as divorce gathered momentum in America?"
The problem with this article is the word "evangelical" It is set up as a "strawman"
This is a word which has become meaningless in the church and out.
In this group which Jesus points to... "22 Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?" (Matt 7) = They would have been called "evangelicals" today.
But Jesus calls them.... "23 And then will I profess unto them, I never knew you: depart from me, ye that work iniquity."
The Remnant is a lot smaller than Mr Mohler appears to perceive.