It is a well-known fact that, 43 years after the revolution of May 1810 we commemorate today, Argentina used the Constitution of the UnitedStatesasamodelforitsownfundamental law. Another well-known fact is that Argentina deviatedfromthismodelregardingsomematters of significance. It is not so well-known, however, that a crucial matter where the Constitution drafted in 1853 deviated from the American text is the distribution of powers to make and apply the Law. Pursuant to the American model of 1787/ 1789, the powers not delegated to the Federal Government are reserved to the states. This general principle of federalism, which permeates the whole constitutional design, is embodied in the Tenth Amendment.1 The Argentine text of 1853 embraced the general principle of federalismandalsolaiditdownexpresslyinArticle101 of the Federal Constitution (currently, Article 121)...