This essay draws on a recent study of how the international community has dealt with the need to construct or reconstruct the security sector in six countries where there has been severe conflict leading to significant international engagement. Various factors are identified as having been critical in shaping the outcome of (re)construction efforts, and they are evaluated from several perspectives. The author observes that external actors have tended to take a limited and unbalanced approach to the security sector, focusing on building the efficiency of statutory security actors, and neglecting the development of managerial and governance capacity. He concludes that while programmes tended to become more effective after the first major post-Cold War effort was undertaken in Haiti in 1994, the plight of the reconstruction effort in Afghanistan after 2001 may point to a reversal of this trend.