This quote from Angelo Codevilla sums up the problem most Republicans have with Republicans in government while also explaining the popularity of Donald Trump.
No prominent Republican challenged the ruling class’s continued claim of superior insight, nor its denigration of the American people as irritable children who must learn their place. The Republican Party did not disparage the ruling class, because most of its officials are or would like to be part of it. – Angelo M. Codevilla – Summer 2010
Whatever Trump really is, or you may think he is, he presents himself as the answer to this problem in language meant for the working middle-class American. A populist message delivered to a people tired of sending Republicans to Washington only to see them scramble to join the thing they sent them there to oppose.
For a refresher on Codevilla look here (free). For the same but with more detail go here (Purchase required). I highly recommend either or both, with regular re-readings at least every six months.