James Buchanan’s Public Principles of Public Debt is universally associated with the claim that debt allows the cost of public activity to be shifted onto future generations. This claim treats a generation as a unitary and acting entity. While such treatment is standard fare for macro theorists who work with representative agents and societal averages in place of the individuals who constitute a society, such treatment conflicts with Buchanan’s Cost and Choice and, indeed, his entire oeuvre. This essay undertakes an act of rational reconstruction that renders his 1958 claim both reasonable and consistent with his formulation in Cost and Choice where cost can be experienced only by individuals. This rational reconstruction reveals a cleavage between public debt approached through macro theory and public debt approached through public finance. Public Principles was generally treated by economists as macro theory when it was really about public finance and political economy.