Since constitutional aspects of public management reforms are rarely debated, scholars and politicians alike end up underestimating two fundamental problems in modern democratic political systems. The first concerns the effects that public management policies may have on power allocation within and outside the public sphere. Here the lack of critical analysis and debate concerns the fact that seemingly technical adjustments of the government’s tool box may end up changing the power allocation among actors vertically as well as horizontally. The second perspective, and the one to be discussed in this paper, concerns the reverse relationship, i.e. how constitutions influence public management policy reforms. The last decades have resulted in a global spread of ideas regarding how governments should manage public authorities and the public sector. In this paper we aim at identifying constitutional variables to explain the variation of how specific public management tools are applied in different contexts.