Following the financial crisis, governments of industrialized countries have undertaken major programs to stimulate demand and to recapitalize banks. As a result, levels of public debt rose sharply, and they will probably continue to do so in the near future in the OECD countries. However, there is no consensus on the effects of public debt on the economy. This article examines the theoretical contributions to this debate. First, we question the possible existence of a desirable public debt target, and then we focus on two major risks associated with long-term indebtedness: its impact on growth and the stability of the policy mix.