Nationbuilding or state-building efforts are almost always described in terms of empowering local authorities to assume the responsibilities of conventional sovereignty. The role of external actors is understood to be limited with regard to time, if not scope, in the case of transitional administration exercising full executive authority. Even as the rules of conventional sovereignty are de facto violated if not de jure challenged, and it is evident that in many cases effective autonomous national government is far in the future, the language of diplomacy, the media, and the street portrays nothing other than a world of fully sovereign states. The next section of this article describes the basic elements that constitute the conventional understanding of sovereignty and provides a taxonomy of alternative institutional forms. It is followed by a discussion of the ways in which conventional sovereignty has failed in some states, threatening the well-being of their own citizens and others. The inadequacy of the current repertoire of policy options for dealing with collapsed, occupied, and badly governed states-governance assistance and transitional administration-is then assessed. The possibilities for new institutional forms-notably shared sovereignty and some de facto form of trusteeship-are examined. Included is a discussion of why such arrangements might be accepted by political leaders in target as well as intervening states.