International politics are undoubtedly in transition along recognizable lines. The resulting disruptive effects on the international institutions founded after World War II are no less evident. Such times demand a principled basis to guide the politics of structural choice for global governance. This article provides a heuristic argument about the most general issues of structural choice, focusing on how to designate the constituencies of the global governance system and the mode of their representation. A concrete illustration of this heuristic argument is provided to demonstrate its plausibility as a starting point for deliberation about the structure of a global governance system.