Here is an interesting defector: Paul Wehner is notable because he’s an old white guy and has served in three Republican administrations. But in one fell swoop he’s breaking ranks, both with evangelicals and Republicans.
He may over-romanticize evangelicals of the past, but I think he’s certainly correct to cite a friend of his who says, “the term [“evangelical”] is now so stained as to ruin my ability to be what evangelicalism was supposed to be.” For sure, dude, and this is how I felt, a decade ago, when I defected.
In fairness to evangelicals, it’s hard to see what’s happening when you’re in the bubble. For anyone on the inside of evangelicalism (or any group/institution), it can be hard to see how tainted your tribe’s reputation has become. (Another poignant example of this: The Democrat Party.
From the inside, you might get frustrated with your group/tribe, but you definitely don’t want to see the ship sink, you want to keep it afloat, ride the storm, and hope to patch ‘er up and keep sailing. Most imporatantly, from the inside, you see all the good, and you love the tribe and you tend to focus on the good. It isn’t always easy to see when it’s time to make a radical change.
More and more, though, folks are realizing that they’ve been soaking in the bath, now, for quite a while. The water is cold and kind of gross, discolored, with some hair and other strange particals floating on the top. It’s time to drain the tub and get out of the bath, time to blow out those scented bathroom candles and move on with life. And now, even a few old white dudes are realizing that it’s time to pull the plug.
Here’s a bit more from Wehner’s op-ed, a section that I found interesting:

Paul Wehner, NYT, Dec 9, 2017
From The New York Times, Why I Can No Longer Call Myself an Evangelical Republican