In preparing for my micro final, I'm re-reading Donald Wittman's critique of public choice economics. PC (in its most basic form) claims that the political sector rarely achieves the efficiency of free market economics because of the incentive structure in play.
Wittman disagrees, claiming politics is as efficient as economics. I disagree with him but one claim he makes bears special mention. "Candidate develop reputations. If they have not kept their campaign promises in the past, they are less likely to be reelected or elected to a higher office. In economic markets, a firm's "goodwill" may be capitialized in the value of the firm and ultimately sold." (1397)
Implict in Wittman's reasoning is an astonishing assumption: candidates are not package deals.
In economics, there is not any product that, all at once, promises to make your car run smoother, feed your baby, improve your productivity, clean your air, secures your retirement and educates your child. Yet these (and more) resemble the standard claims of politicians. And while any one of these promises I can check and punish for on a product-by-product level, a candidate asserts to be a master at all of these. It becomes too easy to forget what he's promised to do and impossible to punish him for just that violation.
I'd buy Wittman's argument more if we lived in a world where each politician was only allowed on campaign promise and could only work on that one thing if elected. (Though there would still be other problems with this world.)