While most economists accept the idea of externalities and most believe that economic gains would result if those externalities could be internalized, this does not count for much in the current political debate about, say, atmospheric carbon or the Chesapeake Bay water quality problem. To understand why, we have to realize that the people generating additional atmospheric carbon and nutrient pollution to the bay are we ourselves. In order to agree to Pigovian taxes, we would have to accept that we are the source of the problem, and this is a difficult thing for people to do. Somehow we convince ourselves that it is somebody else's pollution contribution that is a problem, not ours. In order to get elected, our political leaders venally support us in this belief; economists are easy to ignore.