In response to the democratic boundary problem, two principles have been seen as competitors: the all-affected interests principle and the all-subjected principle. This article claims that these principles are in fact compatible, being justified vis-à-vis different functions, accommodating different values and drawing on different sources of normativity. I call this a ‘function-sensitive’ view. More specifically, I argue that the boundary problem draws attention to the decision functions of democracy and that two values are indispensable when theorizing how to regulate these (...) functions: procedural fairness and political autonomy. While the value of procedural fairness is best promoted through a version of the all-affected interests principle, applied to decision making generally, it is argued that political autonomy is best promoted through a version of the all-subjected principle, applied to coercive decision making specifically. The article concludes by drawing out some practical implications of the function-sensitive view for the case of immigration and border controls. (shrink)