http://www.thedailybeast.com/articles/2015/01/28/you-betcha-i-was-wrong-about-sarah-palin.html
In fairness, Palin was once a reform-minded governor who enjoyed an 88 percent approval rating. But something happened on the way to Des Moines. I suspect the most vicious attacks (especially the Trig Truther stuff) radicalized her and embittered her, but I also suspect she also took the easy way out.
Or maybe the analogy that fits better is this ...
http://prospect.org/article/what-ever-happened-glenn-beck