International audienceUsing an approach that embodies an explicit tradeoff between need and governance considerations, we propose an optimal aid allocation formula. We first assume exogenous, then endogenous governance. In the former case, a central concept is need-adjusted aid effectiveness while in the second case the donor has policing instruments under the form of monitoring and sanctioning capacities. We show that external disciplining has two advantages when the donor is sensitive enough to poverty intensity: (1) to cater to poor countries to a greater extent than is possible when local governance cannot be influenced by external forces, and (2) to respond (non-perversely) to improvements in the local governance of a country by raisin...