Let's start with the theory-qualifying snippet:
Where politicians and parties go wrong is when they adjust the policies they favor in order to be able to use the words that test well, and then mistakenly believe that the underlying policies are actually popular.Most of us would not have any problem with that statement. But under Bernstein's theory of representation, it's not entirely clear that it matters whether "underlying policies" are popular, if the "words that test well" get the speaker elected or reelected. So, for a second time, let me pick a bone with the joyous cynicism animating Bernstein's celebration of a purely contractual relationship between elected official and voters.