Jonathan Chait has hit upon the answer to the problem of Democratic electoral failure. Unless I misunderstand him he's advising Democrats to leave talk of principles and ideas to the Republicans, who are apparently better at it, and just promise to govern on an ad hoc basis.
Tired of conceding elections to Republicans, Chait wants to concede the sphere of principles to them as well. His argument, I think, is that Republicans articulate a lot of high-sounding principles about low deficits and small government, but they govern according to the expediencies of the moment. This doesn't seem to hurt them at the polls so the Democrats ought to go and do likewise.
I doubt his advice will be followed, nor should it be, but if it were it might portend the end of ideology in our time.