Public management has been dominated by the quest for efficiency and has left us with fundamental ethical questions that remain unresolved. It is argued that Machiavellian thought may provide us with concepts and tools applicable to ruling societies confronted with uncertainties and change that are (1) in line with the most recent insights into institutional evolution and (2) appropriate to solve complex decision-making problems. The common good — a central concept of Machiavelli's thought — appears to be an invisible hand that lowers the transaction costs and acts as the keystone of complex public affairs thinking. This analysis is illustrated by a comparative case study of the two management projects of infrastructure crossing the Alps, the AlpTransit in Switzerland, and the Lyon Torino Link. It concludes with a proposal to upgrade the research program in public management that allows effectiveness (legitimacy of the ends) and effectiveness in its implementation. Points for practitioners The mainstream of public management theories and reform has been dominated by the quest of efficiency as a Holy Grail. I argue that theses reforms didn't deliver with their promises and left us with fundamental ethical questions unresolved: doing things right do not answer to the question of doing the right things. The main reason is a profound misunderstanding of the very nature of the ongoing change process that makes any kind one size fits all recipes inappropriate. Such a sea change occurred in the Renaissance era and Machiavelli bequeathed us a comprehensive understanding of how to rule a public body in a changing and uncertain world. I explain Machiavelli's misunderstood legacy and apply his teaching to analyzing two huge management projects of public infrastructures. I conclude on what has to be upgrade in the research programmes in public management to confront with the challenges of our era that call for a back to basics of classical political philosophy
