Public policies are supposed to be transitory measures meant to faceand solve public problems. Constitutional design, by contrast, involves per-manent decisions adopted to rule the inner workings of the polity and itsgovernment. Although policy is most often imagined as transitory and con-stitutional law as permanent, some policy decisions reconfigure constitu-tional design permanently. This Article proposes a new analytic frameworkfor rendering visible and understanding the impact of policy decisions onconstitutional design. We call this framework “constitutional costs,” simul-taneously pointing to the fields of constitutional law and policy analysis.Transcending the categories of constitutionality or unconstitutionality of alegal change or policy allows for a more robust critical assessment of theconstitutional implications of policy decisions. We posit that, independentlyof their constitutionality, policy decisions and their consequences can comeinto tension with existing core constitutional commitments, significantly un-dermining them. Understanding how these dynamics play out in a longchronological arch is complex but important, for they can significantlychange the way a constitutional system works, even if the depth and breadthof the changes are not acknowledged as they are adopted and implemented.By looking in detail at the war on drugs—a complex policy—in twosalient case studies—Mexico and Colombia—we flesh out our analyticalproposal and exemplify how it can be deployed. The Article focuses on twocase studies, but it does not purport to limit the analysis of constitutionalcosts to either of those two countries, or to the specific “war on drugs”policy. We offer these case studies so as to simultaneously illustrate theapplications of the framework and lay the groundwork for comparativeanalysis of constitutional costs.