|Alex Alí Méndez Díaz|
The requirement on judges resulted from a 2015 ruling by the Supreme Court of Justice of the Nation (SCJN) that declared all bans on marriage equality unconstitutional. The Supreme Court, however, has no power to end all states' bans simultaneously, and can only force individual states' bans out of existence in specific situations.
The ruling says: "Marriage. The law of any federative entity that, on the one hand, considers that the purpose of it [marriage] is procreation and/or that defines it as that which is celebrated between a man and a woman, is unconstitutional." ("Matrimonio. La ley de cualquier entidad federativa que, por un lado, considere que la finalidad de aquél es la procreación y/o que lo defina como el que se celebra entre un hombre y una mujer, es inconstitucional.")
The SCJN ruling resulted from a project by activist-lawyer Alex Alí Méndez Díaz and his organization México Igualitario that involved getting enough identical cases before the Supreme Court from multiple states to create an opportunity for the court to declare "jurisprudence" against bans on marriage equality.
Below are the states where same-sex couples can marry normally (though a minor additional procedure is still required in Baja California and Oaxaca). Some states passed marriage equality legislatively, some decided administratively to stop enforcing their unconstitutional bans, and three states' bans were struck down by the Supreme Court via a specific procedure described below.
• Baja California (administrative)
• Campeche (legislative)
• Chiapas (SCJN ruling)
• Chihuahua (administrative)
• Coahuila (legislative)
• Colima (legislative)
• Jalisco (SCJN ruling)
• Mexico City (legislative)
• Michoacán (legislative)
• Morelos (legislative)
• Nayarit (legislative)
• Oaxaca (administrative)
• Puebla (SCJN ruling)
• Quintana Roo (administrative)
• There are also various cities that stopped enforcing their state's ban, including Santiago de Querétaro, capital of Querétaro state.
As to Chiapas, Jalisco and Puebla, whose bans were terminated by the Supreme Court, here's what happened: When any law is passed in Mexico and takes effect, there is a 30-day window for certain governmental entities to challenge the law with an "action of unconstitutionality" at the Supreme Court. What Chiapas, Jalisco and Puebla did is make some changes to their marriage laws, unrelated to marriage equality, and the revised paragraphs also included existing man-woman language. The revisions qualified as "new" laws that could be challenged during the 30 days after they took effect. The National Human Rights Commission filed actions of unconstitutionality against the man-woman language and the SCJN struck down the three states' bans in separate rulings in 2016 and 2017. The states likely were unaware they were setting up their same-sex-marriage bans for strikedown.
Remarkably, given that this process led to marriage equality in three states that weren't ready to pass marriage equality, the state congress in Nuevo León did the same thing in January 2018 and the National Human Rights Commission pounced again. The Supreme Court accepted the case and the Nuevo León ban's days are numbered.
Going forward, it is likely that additional state legislatures will pass marriage equality and that officials in additional states will stop enforcing their unconstitutional bans by administrative fiat. In addition to the coming Nuevo León ruling, there also is a chance some states' bans could be terminated by the Supreme Court via a different procedure.
That could happen if officials in a given state repeatedly appeal amparo cases to a federal appeals court and lose five times in a row (they would always lose because of the 2015 ruling), which would create jurisprudence against that state's marriage ban. If the appellate court then forwarded the results to the SCJN, the SCJN could move against that state's legislature and make it repeal its ban. (For several states, some of the five necessary appellate rulings already happened during and after the litigation that led to the 2015 Supreme Court ruling.)
A new federal Congress was seated Sept. 1, 2018, and a new, leftist president takes office Dec. 1. There are some indications that Congress could again consider legislating around marriage equality nationally. That would not change the number of states with marriage equality, but it would cement recognition of married same-sex couples for federal purposes like taxes, immigration, health care and social security, and allow same-sex couples to marry in Mexican embassies and consulates abroad, said Geraldina González de la Vega, a constitutional lawyer who teaches at Ibero-American University in Mexico City.
ADOPTION: Same-sex couples have adoption rights nationwide. The Supreme Court reiterated its jurisprudence in 2016, writing: "ADOPTION. The best interest of the minor is based on the suitability of the adopters, within which are irrelevant the type of family into which [the minor] will be integrated, as well as the sexual orientation or civil status of [the adopters]." ("Adopción. El interés superior del menor de edad se basa en la idoneidad de los adoptantes, dentro de la cual son irrelevantes el tipo de familia al que aquél será integrado, así como la orientación sexual o el estado civil de éstos.")