As economists increasingly embraced benefit-cost analysis during the middle decades of the 20th century, they faced several challenges. One challenge was to reconcile the tension between two visions, long existing side-by-side in the profession, for the place of the economist in policy analysis. One vision limited the economist to providing positive analysis for use by authorized decision-makers; the other allowed normative judgments. This tension came to a crisis when, in the 1960s, the Water Resources Council introduced multi-objective benefit-cost analysis into water agencies practices. The surrounding debate highlights the way philosophical differences can drive the technical details of policy analysis, the way political debates can overshadow academic ones, and the way even social scientists working together in a narrow subfield can profoundly misunderstand one another.