One of the most heated debates over Mexico’s ratification of the Rome Statute for the International Criminal Court dealt with a violation of the non bis in idem principle. Whether one agrees with the jurisdiction of the ICC or not, what came to light with this disagreement is that the Mexican Constitution might be at odds with international human rights standards with regard to this Principle. Consequently, there is a need to make a comparative assessment between both bodies of law. While the obvious starting point is Article 23 of the Mexican Constitution, which states this principle, an extensive study cannot stop there but must include its judicial interpretation. Furthermore, only the precedents that seem to stretch the application of the principle will be considered, because it is through these borderline cases that we can establish the extent of the Principle (It should be noted that this approach is not common, since there is no system of precedents in Mexico; however, it is only through the judicial gloss that we can ascertain the extent of the Principle). Next I will examine (using the same method) International Human Rights Law, in particular the American Convention on Human Rights, because it is the only international instrument that includes a non bis in idem provision that applies to Mexico. Once the descriptive part of the paper is done, there will be enough material to make a full comparative analysis to determine whether Mexican regulation of non bis in idem fulfills international human rights standards and, in case this is answered in the negative, what is needed to comply.
