Constitutional reform in Mexico: no limits to ius sanguinis

Henio Hoyo (CIDE, Mexico City / UDEM, Monterrey)

An overview of the Mexican citizenship regime

The Mexican citizenship/nationality regime (namely, ‘membership’ in the Mexican nation-state, either by birth or by naturalisation) was established by articles 30, 32 and 37 of the 1917 Constitution and the corresponding Nationality Law. Initially, it was based on ius sanguinis with supplementary ius soli for those born in Mexico to foreign parents (only upon request after reaching the legal age and demonstrating six years of residence). A comprehensive 1934 reform reversed this principle. It instituted the current nationality regime, based on unrestricted ius soli as the primary criterion, with supplementary and qualified ius sanguinis for those born abroad. While in 1934 patrilineal transmission of citizenship was heavily favoured (Mexican mothers abroad could only pass down their nationality in the case of an ‘unknown’ father), gender-neutral transmission was adopted in 1969.

As a result, (i) all children born within the Mexican territory (or Mexican ships/airplanes) are automatically Mexican nationals by birth, regardless of the nationality of their parents; and (ii) those born abroad to a Mexican father between 1934 and 1969, or those born abroad to a Mexican father or mother from that year on, are also Mexicans by birth. In both cases, the claim to dual nationality was tolerated for children, but it was explicitly forbidden for adults; so, the person had to choose between nationalities upon reaching legal age.

This did not change until 1997, when a far-reaching constitutional reform, aimed to protect the large Mexican diaspora (particularly in the United States) made Mexican citizenship-by-birth both ‘permanent’ and ‘non-forfeitable’. As a result, all limitations were abolished for Mexicans by birth to become dual nationals. A new Nationality Law followed in 1998, allowing for the recovery of citizenship for those Mexicans who had renounced it before (to naturalise in USA for instance). With some limited changes, provisions of this law are still in force.

The 1997 constitutional reform marked a radical shift from the twentieth century nationalist ethos and restrictive approach to citizenship and migration regulation, as well as to relationships with the diaspora. Even so, the same reforms also introduced some quite important limitations to dual citizenship. Arguably, these were intended as a barrier to too much ‘foreign interference’.

  1. Dual citizenship would be allowed for citizens by birth only. Naturalised Mexicans would be (and still are) barred from either taking another citizenship, as well as from retaining their original one after naturalisation.
  2. Both naturalised and dual citizens were excluded from holding a number of jobs and positions, particularly, but not exclusively, in the public service.
  3. Transmission of citizenship via ius sanguinis was conditional upon the parent(s) being either born in Mexico (thus having citizenship via ius soli) or being naturalised Mexican(s).

The last point implied that, in most cases, transmission of citizenship via ius sanguinis was limited to the first generation born abroad. So, grandchildren of Mexicans would not be automatically citizens by birth – unless their parents returned to Mexico to give birth. Not returning to Mexico implied a risk of statelessness for such children, for instance if their country of birth did not apply ius soli, or if the parent had their foreign citizenship revoked and could thus not pass it via ius sanguinis. Admittedly, Mexico partially addressed such concerns as early as 2012, when a reform to article 20 of the Nationality Law provided facilitated naturalisation to third-generation migrants born abroad who would be at risk of statelessness or otherwise stateless. However, this reform was quite limited and also demanded complex procedures and requisites for the parents and the children concerned.

The rationale and procedure of the 2021 Constitutional reform

In September 2018, Senator Olga Sanchez Cordero (from the ruling National Re-generation Movement party, MORENA) presented a bill to amend article 30, section A, fraction II of the Mexican Constitution. Senator Cordero proposed to supress the wording that required parents to be born in Mexico in order to transmit Mexican citizenship to children born abroad. In practical terms, such amendment would lift all limits of transmission via ius sanguinis to Mexicans born abroad.

Officially, the rationale of the bill was avoidance of the risk of statelessness for third-generation migrants – already attempted by the 2012 partial reform. Such risk was greatest for Mexicans living in a country applying the ius sanguinis principle, but that is not the case for the vast majority of Mexicans abroad: 97% of them live in the United States (US), a country that applies ius soli. The actual rationale of the bill was different; namely, to pre-emptively protect Mexican migrants and their children from the outcomes of the heavy-handed decisions and incendiary narrative of the Trump administration. In fact, shortly after the bill was passed, the then US President Donald Trump stated in an interview that he would seek to end ius soli in the US by means of an executive order. While his attempt was unsuccessful, the possibility of a future change in the citizenship laws of the US, which could create hundreds of thousands of stateless persons with Mexican ancestry but no Mexican citizenship, was an evident source of concern.

Furthermore, the internal situation in Mexico in 2018 played an important role for this legislative change. First, the general elections of July 2018 brought MORENA and its coalition allies to power: not only did they win the Presidency by a landslide, but also the majority in both Chambers, five out of nine gubernatorial races, and most local congresses. This provided MORENA and President-elect López Obrador with a unique opportunity to introduce large reforms with both legitimacy and democratic support, and also without the real need to seek consensus with the opposition parties. Second, the high profile and experience of Sánchez Cordero who proposed the bill also played a role: she was a well-known Supreme Court Justice for ten years before being elected Senator. Sánchez Cordero was very close to President-elect López Obrador during his campaign, leading her to become Secretary of State in December 2020, mere two months after she introduced the bill.

The discussion of the bill took place only in October 2020. The approval was swift – first it received unanimous support in the Senate, and then was voted by 396 out of 397 parliamentarians in the Chamber of Deputies, with no changes at all. On 14 December 2020, the bill was sent to the 32 state legislatures, as constitutional changes need the approval of at least half plus one. This was achieved on 18 February 2021, and the publication in the Official Gazette (Diario Oficial de la Federación), which is the last step of the process, is likely to follow shortly.

Pending issues

Once approved, the constitutional amendment will lead Mexico to apply both unrestricted ius soli and unrestricted ius sanguinis in citizenship attribution. However, details on the implications of this reform and the procedural matters involved are not clear as of yet.

For instance, the 1998 Nationality Law does not regulate the attribution of citizenship by birth either through ius soli or through ius sanguinis. Rather, it mentions the corresponding article 30 of the Constitution only once and only sporadically. This strange omission of such a key topic as citizenship by birth in the Nationality Law is the consequence of it being published in 1998, in the wake of the reform allowing dual citizenship. Thus, the Law focuses heavily on restrictions related to dual nationality, such as those related to holding certain positions (as mentioned above) and on the regulation of naturalisation. The same applies to the corresponding Reglamento (third-level regulations): it does not deal with ius soli or ius sanguinis at all. Only the Constitution does.

The advantage of this is that neither the Nationality Law, nor its Reglamento would need to be repealed due to the current Constitutional amendment. In theory, this facilitates the entry into force of the new dispositions, but it also implies that some key aspects and consequences of the reform have not been discussed and remain unclear. For instance, right now it is unknown whether if the acquisition of Mexican citizenship by ius sanguinis abroad will be automatic or granted through registration / declaration. Even more importantly, the earlier reforms that allowed dual citizenship have been applied retroactively. Will this be the case with the current amendment? If so, given the migratory characteristics of Mexico, potentially a very large number of persons with Mexican ancestry – hundreds of thousands, or even millions – could have a claim to Mexican citizenship. Therefore, such key details still need to be addressed. If this is not done through a wholly new Nationality Law and Reglamento, it could be achieved by the addition of new articles or even sections to the existing ones. This implies a further legislative process which, in view of the incoming 2021 mid-term elections, will probably take quite some time.