This Essay explores an entanglement of ends and means between two seemingly disparate parts of the Constitution: the Fourth Amendment and the separation of powers. Not only do these two elements of the Constitution share a common ambition; they are also intertwined in practical operation. The vindication of Fourth Amendment interests, however defined, depends on a measure of institutional differentiation between the branches of government. That predicate, however, has eroded over time. In its absence, difficult questions arise about how Fourth Amendment values are best implemented and whether their realization will in the end hinge on private rather than on state action.