… is from pages 184-185 of James Buchanan ‘s 1979 collection What Should Economists Do?  (H. Geoffrey Brennan & Robert D. Tollison, eds); specifically, it’s from Jim’s 1978 essay “Public Choice and Public Finance”:
In a summary definition, public choice is the analysis of political decision-making with the tools and methods of economics. For specific precursors, we look to the works of Continental scholars like [Emil] Sax, [Ugo] Mazzola, [Maffeo] Panteleoni, [Antonio] De Viti de Marco, and, most important, Knut Wicksell, all of whom wrote before the end of the nineteenth century. The works of these scholars differed substantially one from another, but all shared a common objective, which was to bring the public economy within the analytical framework that had seemed so successful in explaining the working of the private economy. To do this, these scholars almost necessarily were forced to pay some attention to the political decision structure within which taxing and spending choices were made.
DBx: Buchanan often explained how his mind was turned toward a public-choice manner of analyzing government and collective decision-making by his reading of these Italian public-finance theorists and by his stumbling upon, very early in his career, the work of the Swedish economist Wicksell. How Nancy MacLean concludes from any of this history of Buchanan’s thought in particular, or of public-choice scholarship generally, that it was a secret racist plot – influenced heavily by the the work and loathsome racist ideals of John C. Calhoun (whom Buchanan never cites ) – is beyond comprehension.