Status of Human Rights Treaties In Mexican Domestic Law

Christina M. Cerna
February 23, 2016


The Mexican Supreme Court issued a judgment on September 20, 2013 that resolved a “conflict between jurisdictions” (contradicción de tesis) and led to compliance with the Inter-American Court of Human Rights’ judgment in the Radilla Pacheco case.[1] This judgment transformed human rights into the centerpiece of the Mexican legal order and led to the United Nations awarding the Mexican Supreme Court its UN Prize in the field of Human Rights on December 10, 2013 for “promoting human rights through its interpretation and enforcement of Mexico’s constitution and its obligations under international law.”

The Status of Human Rights Treaties in Mexican Domestic Law

Two Mexican Circuit Courts had issued contradictory opinions with regard to the status of international human rights treaties in Mexican law.  The First Circuit Court (Séptimo Tribunal Colegiado en material Civil del Primer Circuito) declared that “international treaties hierarchically are located above federal laws but below the Federal Constitution,” whereas the Eleventh Circuit Court (Primer Tribunal Colegiado en Materias Administrativa y de Trabajo del Décimo Primer Circuito) declared that “when conflicts arise in relation to human rights, international treaties must be considered at the level of the Constitution.”

The Supreme Court, however, in its judgment, jettisoned the concept of “hierarchy,” and by a majority of ten votes, decided that human rights are recognized as a whole as a kind of amalgam, whether they derive from the Constitution or from international treaties to which Mexico is a party. The constitutional reforms of June 2011 fostered this new approach that human rights norms, regardless of their source, are not organized in a hierarchical relationship. The Supreme Court also noted, in a much criticized addition, that “when the Constitution establishes an express restriction on the exercise of human rights, this restriction must be respected.” In this context, human rights, regardless of their source, constitute the parameter of control of constitutional regularity according to which the validity of all the norms and acts of authority that form part of the Mexican legal order must be analyzed.

The Mexican Supreme Court’s position as to the place of international treaties in the Mexican legal order has evolved over time. As recently as 1992, it placed international treaties at the same level as federal laws, emphasizing that both federal laws and international treaties were below the Mexican Constitution. Then, in a later case, it established that international treaties in agreement with the Constitution are placed above federal and local laws but below the Constitution. And more recently, in 2002, it established the following: 1) the existence of a higher legal order, of a national character, comprised of the Constitution, international treaties, and general laws; 2) the supremacy of international treaties in the face of general, federal, and local laws; and 3) the existence of an international vision of the Constitution by which, in compliance with the Vienna Convention on the Law of Treaties, Mexico cannot invoke its internal law as an excuse for the failure to comply with obligations contracted with other international actors, since all treaties in force create obligations for the parties and must be complied with in good faith.

Article 133, the Supremacy Clause of the Mexican Constitution, was not subject to modification during the constitutional reform process and postulates the Constitution as the principal norm below which the normative hierarchy of the Mexican legal order has been constructed. Within this formal hierarchy of norms, international treaties are below the Constitution and above the rest of the legal norms that form part of the Mexican legal order.

But where in this hierarchy are international human rights treaties? Are they below the Mexican Constitution together with other international treaties? The June 2011 constitutional reform process situated the individual in the central axis around which the reform would be articulated. The previous Article 1 of the Mexican Constitution, “Individual Guarantees,” provided: “In the United States of Mexico every individual will enjoy the guarantees that this Constitution grants, which cannot be restricted or suspended, except in those cases and under the conditions which it itself establishes.” The title “Individual Guarantees” was transformed into “Human Rights and its Guarantees,” emphasizing the changed focus on the centrality of human rights in the Constitution.  In addition, the language of Article 1 was expanded to reflect this new recognition of human rights: “In the United States of Mexico all persons shall enjoy the human rights recognized by the Constitution and international treaties to which Mexico is party, as well as the guarantees for their protection, the exercise of which cannot be restricted or suspended, except in the cases and under the conditions established by this Constitution.”  The new phrasing reflects the universal conception of human rights as inherent in the human being and recognized, rather than granted (otorgado) by the state, a term burdened by the possibility that the state that grants them can also take them away. More importantly however, it provides that human rights, whether derived from the Constitution or an international treaty and its guarantees, will be protected on an equal footing.

Traditionally, the Mexican Supreme Court noted, international human rights treaties were distinguished from other international treaties. Article 1 of the Constitution recognizes that human rights set forth both in the Constitution and in international treaties to which Mexico is party are protected equally, without reference to the subject matter covered in the international treaty. This means that rights which are covered in international treaties that are not considered “international human rights treaties,” such as the paradigmatic example of the right to notification, contact and consular assistance set forth in the Vienna Convention on Consular Relations (VCCR), can be incorporated into the catalog of human rights included in the Constitution. In Advisory Opinion No. 16, requested by Mexico of the Inter-American Court of Human Rights, the Court held that denial of the VCCR rights was a denial of due process, a human right, despite the fact that the International Court of Justice  declined to examine whether VCCR rights were human rights in the Avena case.[2]

Consequently, the Mexican Supreme Court interprets the content of Article 1 of the Constitution as an amalgam or “bloc” of human rights, the source of which may be the Constitution or an international treaty and this amalgam of norms comprises the new parameter of control of regularity or validity of the norms of the Mexican legal order. In the Inter-American Court’s judgment in the Radilla Pacheco case, a case involving a military court’s failure to investigate a forced disappearance, the Court called on the Mexican judiciary to carry out an ex officio “control of conventionality” [convencionalidad] of its domestic legislation to determine whether it conforms to the American Convention on Human Rights and noted that the failure to do so comprises a violation of Article 2 of the Convention.[3]

The Status of Adverse Judgments of the Inter-American Court of Human Rights in Mexican Domestic Law

With regard to the normative status of adverse judgments of the Inter-American Court of Human Rights, the First Circuit decision declared that “international jurisprudence was useful to help orient domestic courts in human rights matters,” whereas the Eleventh Circuit declared that “international jurisprudence in human rights matters was obligatory.” An earlier July 14, 2011 opinion of the Mexican Supreme Court, which had clearly guided the decision of the First Circuit, found that the Inter-American Court’s jurisprudence served as “guidance” for the Mexican judiciary.[4]  In the April 25, 2014 decision, however, the Supreme Court, by a majority of six votes, decided that the jurisprudence of the Inter-American Court of Human Rights is binding on all Mexican judges (both federal and state), provided that the interpretation is the one more favorable to persons (the principle pro persona).

The basis for this decision builds on the reform of the second paragraph of Article 1 of the Mexican Constitution, which provides that human rights norms shall be interpreted in conformity with the Constitution and international treaties. When the norms conflict, the decision shall be made pursuant to the principle pro persona, that which is more favorable to persons. 

The Mexican Supreme Court held that the reasoning behind the judgments of the Inter-American Court was legally binding on Mexico, whether or not Mexico was a party to the case in question.  This is a very progressive evolution, since Article 68 of the American Convention  only requires states parties to comply with the judgment of the Court in cases to which they are parties. The jurisprudence of the Inter-American Court, however, has evolved beyond the text of the American Convention, as the concurring opinion of Ad Hoc Judge Ferrer Mc-Gregor Poisot makes clear in outlining the history of the “control of conventionality doctrine,” which requires states to conform their domestic legislation not only to the American Convention but also to the Inter-American Court’s interpretation of the terms of the Convention.[5]

In all cases where it is possible, national judges are required to harmonize national jurisprudence with the jurisprudence of the Inter-American Court; if it is not possible to reconcile the two, the national judge is required to apply the jurisprudential criterion which is more favorable to the protection of the human rights (the pro persona principle).


In compliance with the Inter-American Court’s judgment in Radilla Pacheco, on June 13, 2014, the Mexican Congress published its military justice reform decree in the Official Gazette (Diario Oficial de la Federación). This decree provided, inter alia, that human rights violations and other crimes committed by military personnel against civilians will now be subject to prosecution in civilian, not military courts. The Inter-American Court, in Radilla Pacheco and a number of other cases, has consistently held that military courts do not have the competence to investigate, prosecute and punish the perpetrators of human rights violations. Taking human rights cases out of the hands of military courts is a major strike against the impunity inherent in the Mexican military justice system.

Human rights groups have expressed concern about provision of reformed Article 1 of the Mexican Constitution that the enjoyment of human rights may be restricted or suspended, in cases and under conditions established by the Constitution, which was echoed in the Supreme Court’s judgment, and has been interpreted by Amnesty International, for example, as a step backwards in the protection of human rights.[6] The charge is that the Supreme Court should have affirmed the pro persona principle in this context rather than emphasizing the alleged priority of the restrictions in the Constitution over international treaties.

These are issues that will be resolved in the future. Suffice it to say that Mexico has engineered an extraordinary transformation of its internal legal system placing human rights at the center of concern of its Constitution and laws. Its acceptance of the obligatory force not only of the judgments but also the jurisprudence of the Inter-American Court of Human Rights is a shining example of best practices.

About the Author: Christina M. Cerna, an ASIL member, is an Adjunct Professor at Georgetown University Law Center.


[1] Radilla Pacheco v. Mexico, Preliminary Objections, Merits, Reparations and Costs, Inter-Am. Ct. H.R. (ser. C) No. 209 (Nov. 23, 2009).

[2] The Right to Information on Consular Assistance in the Framework of the Guarantees of the Due Process of Law, Advisory Opinion OC-16/99, Inter-Am. Ct. H.R. (ser. A) No. 16 (Oct. 1, 1999).

[3] For a longer discussion of the Radilla Pacheco case, see Christina M. Cerna, Unconstitutionality of Article 57, Section II, Paragraph a) of the Code of Military Justice and Legitimation of the Injured Party and His Family to Present an Appeal for the Protection of Constitutional Rights, 107 AJIL 199 (2013).

[4] Id.

[5] Cabrera García and Montiel Flores v. Mexico, Preliminary Objection, Merits, Reparations, and Costs, Inter-Am. Ct. H.R. (ser. C) No. 220 (Nov. 26, 2010); see Concurring Opinion of Ad Hoc Judge Eduardo Ferrer Mac-Gregor Poisot. Judge Mac-Gregor Poisot was subsequently elected and is currently a judge on the Inter-American Court of Human Rights.

[6] Reference is to “arraigo,” which was introduced into Article 16 of the Mexican Constitution in 2008 and permits the detention of an individual without charge and legal safeguards for up to ninety days. It was designed as a preventive measure to permit the detention of persons suspected of participating in organized crime, but in practice, it has been criticized for being used by the authorities to coerce confessions from suspects under torture, especially detainees held at military facilities. Mexico, in its August 16, 2013 report to the UN Human Rights Council, in the context of the Universal Periodic Review, referred to its plans to reform this article of the Constitution.