Rich Lowry, editor of the National Review, argues that John McCain's natural political posture is as a gadfly, someone who often as not finds fault with his own party as well as the opposition. Lowry's view is that this gadfly tendency has made him a singularly ineffective presidential candidate.
I think I might agree with Lowry. His point that in taking the Jeremiah Wright association off the table, he lost one of his most effective arguments makes sense to me. You might find the article interesting.