This presentation assesses the process of comparing subnational constitutions in federal states from three points of view. First is a top-down assessment of the federal constitution’s subnational constitutional “space,” or competency for the component units to adopt their own constitutions. This is a legal assessment, but influenced by context, with consent and dissent as an important factor. Devolutionary federal states are likely to have narrower space than integrationist federal states. Second is a bottom-up assessment of how the component units actually utilize this competency. This is a political question, which is also influenced by the measure of trust and distrust. Third is a legal assessment of the process of policing the limits of subnational constitutional space, and also on the limits of federal intrusion of such space.