The paper reconstructs the debates in the USA about economic theorizing and policymaking advisory concerning a multi-layered system of governments. Beyond apparent similarities, it highlights the ontological divides between Ostrom-Tiebout- Warren on polycentric governance and Buchanan on competitive federalism on the one side, and Musgrave?s and Olson?s fiscal federalism. It further underlines how such divides - concerning the relative role of individuals, markets, collective author- ities, and social order - echoed similar debates in Europe related to a multi-layered economic system, again depending mostly on different ontological assumptions.