If Krauthammer said this, he "borrowed" it from Rush Limbaugh, who was the originator of the phrase. Regardless, there is much truth and good insight in this obversation.
Liberals are often misguided or stupid. Leftists consider liberals to be Useful Idiots or cannon fodder. The Left is where evil goes to hide. Except when it’s right out in the open, wearing masks and black clothes.