What status do international conventions have in Mexican law?

Article 133 of the Political Constitution of the Mexican United States establishes that ‘this Constitution, the Laws of the Congress of the Union which stem from it and all the treaties which are in agreement with it, adopted by the President of the Republic with the Senate´s consent, are the supreme Law of the entire union. The judges in each State will follow this constitution, its laws and treaties, over and above any dispositions which might exist in the constitutions or laws of States.’¹ Article 15 adds that treaties which ‘change the guarantees or rights of citizens established by this constitution’ must not be adopted.²

The interpretation of article 133 of the constitution has generated some debate about in the hierarchy occupied by international treaties in Mexican law. The interpretation of the National Supreme Court (“Suprema Corte de Justicia de la Nación”, SCJN according to its Spanish acronym) is that international treaties are placed above federal and local laws but below of the constitution.

In 1992, the Law on the adoption of treaties (“Ley sobre la Celebración de Tratados”) came into force. Article 2 of this Law defines a ‘treaty’ as ‘an agreement enforced by international public law, agreed in writing between the government of the United States of Mexico and one or various representatives of International Public Law’ (these are understood as States or international organizations), ‘whether or not it requires for its application adoption of accords on specific matters, of whatever name, by means of which the United States of Mexico takes on obligations.³ It additionally defines ‘ratification,’ ‘accession’ or ‘acceptance’ as ‘the act by which the United States of Mexico makes public to the international community its consent to be bound by a treaty´.’⁴

Related documents:
•  Political Constitution of the Mexican United States (in Spanish)
•  Law on the adoption of treaties (in Spanish)

1. Spanish version of Article 133 of the Political Constitution of the Mexican United-States says: "Esta Constitución, las leyes del Congreso de la Unión que emanen de ella y todos los Tratados que estén de acuerdo con la misma, celebrados y que se celebren por el Presidente de la República, con aprobación del Senado, serán la Ley Suprema de toda la Unión. Los jueces de cada Estado se arreglarán a dicha Constitución, leyes y tratados, a pesar de las disposiciones en contrario que pueda haber en las Constituciones o leyes de los Estados”. Since there is no official English translation of the Political Constitution of the Mexican United States, all translations have been done by Transparencia Mexicana.

2. Spanish version of Article 15 of the Political Constitution of the Mexican United-States "no se autoriza la celebración de tratados que (…) alteren las garantías y derechos establecidos por esta Constitución para el hombre y el ciudadano".

3. Spanish version of Article 2 of the Law on the adoption of treaties: “el convenio regido por el derecho internacional público, celebrado por escrito entre el Gobierno de los Estados Unidos Mexicanos y uno o varios sujetos de Derecho Internacional Público, ya sea que para su aplicación requiera o no la celebración de acuerdos en materias específicas, cualquiera que sea su denominación, mediante el cual los Estados Unidos Mexicanos asumen compromisos".

4. Spanish version of Article 2 of the Law on the adoption of treaties: "el acto por el cual los Estados Unidos Mexicanos hacen constar en el ámbito internacional su consentimiento en obligarse por un tratado".