The principal difficulty: Besley’s neo-Rousseavian aspirations
The use of the “principal–agent” model makes an implicit assumption about the existence of an underlying global optimum or “general will.” This assumption is debatable, and Besley does not defend it sufficiently or even seem to realize how strong an assumption it is. Still, it is standard in the literature, and Besley’s book is a very strong contribution to that literature. Its two greatest strengths are its solid microfoundations, and its use of the classical “comparative statics” approach to analyze dynamics.