Where does a state draw its legitimacy from and how can it bolster it ? Western countries’ answers readily flow from references to their own model. But this question is more complex than it first appears to be, for legitimacy is not decreed, far from it : it is an empirical phenomenon. A public institution that does not meet some outwardly prescribed standards may no less be perceived as legitimate, the authors assert, if those under its jurisdiction consider it to be so. The actual legitimacy of the State rests indeed on a specific and varying mix lifted from a range of sources. It hangs on people’s beliefs, perceptions and (material and symbolic) expectations. It is settled via the constructive relationships between State and society, the weakness and inefficiency of which are standard features of states in fragile situation.