This paper assesses James M. Buchanan's claim of following a positive approach in stark contrast to the normative approach to public finance of Richard A. Musgrave. The goal of this paper is to shed light on the foundations of modern American public finance by analysing one aspect of the methodology of its two most prominent fathers. I show (1) that it is difficult to distinguish Musgrave's and Buchanan's theories of public goods along the positive/normative dividing line and (2) that Buchanan's (...) theory can also be considered normative. In the first three parts, I follow the Weberian methodological tradition in looking for value judgements in the theories, and by reflecting on the nature of ideal types. In the last part, I propose a broader interpretation of Buchanan's methodological stance within the academic context of the 1960s. (shrink)