Abstract: Despite recent criticisms ably presented by Sergio Verdugo, the concept of constituent power seems essential to explain how irregular constitutional changes—those brought about by processes not authorized by the constitution in place—are or become legally binding. Properly understood, the concept of constituent power is not used properly either “in the moment” or prospectively, that is, as partisans advocate for irregular changes or implement irregular processes to put such changes in place. Rather, the concept is properly used only retrospectively, not as Verdugo suggests to support a claim that a unified people actually endorsed the changes when they first occurred, but rather to identify those irregular changes that “stick”—that a nation’s people come over time to accept as legally binding.