Public policy mood, a concept now more than twenty years old, is the measure of left/right preferences over policy choices in American politics. In this essay, I comment on the theoretical need for such a measure and discuss the strategy for estimation. I produce the measure itself for the years from 1952 to 2011. Then I take on the question of how many dimensions of such operational ideology exist. I find two, which is far from novel. But unlike much previous work, my own included, the present analysis utilizes prior theoretical information about the content of the dimensions in order to interpret them. I find the conventional two dimensions, economic and cultural, to be very highly correlated. A final section explores the thermostatic properties of mood.