Report on Mexico

Abstract

This chapter examines the domestic and international law applicable in the framework of mutual legal assistance in criminal matters related to Mexico. It starts with the study of cross-boarder investigations and the obtaining, admissibility and transfer of evidence with an emphasis in the protection of fundamental rights, taking also into account the special regulations in the field of organized crime. Finally, it is analyzed the cooperation between Mexico and the international criminal tribunals, especially the ad hoc tribunals and the International Criminal Court.

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1 Introductory Remarks

The goal of this article is to provide enough information for a comparative study regarding international cooperation and fundamental rights, but it is also to assess the degree of compliance of the national scheme with more universal fundamental and human.

To set out an adequate scope for this analysis, some matters need to be clarified from the outset. The fact that Mexico has a federal system of government is perhaps the most important factor that needs to be considered. This means that each of the 32 states has its own criminal legal system that operates alongside the federal and military procedural codes. However, the Federal Constitution does provide a list of due process provisions and basic principles which all jurisdictions must comply with. Therefore, to simplify the current analysis, only the Federal legal system will be considered.

Another important issue is that Mexico is going through a radical overhaul in its criminal procedure. An adversarial system is being set up, like in most Latin-American countries. While the constitutional scheme is now in place, the different statutory codes still need to be enacted. The current analysis will focus on the new system, especially when addressing fundamental rights, which all have a constitutional basis, and which suffered some changes, particularly regarding due process considerations.

The current state of criminal procedure means that the section dealing with current and future developments is especially important. There are several new bills that will soon be presented to Congress. Consequently, only the bills that are closer to enactment will be considered.

Finally, there is very little legislation regarding mutual assistance at the federal level and practically no case-law. This will seem obvious from the very first section. However, other aspects such as fundamental rights have a more developed framework. In these cases the Federal Constitution, federal law, and case-law will be analyzed, but most of the regulations are in international treaties.

2 Cross-Border Investigations and Fundamental Rights

2.1 Basic Legal Scheme

The legal instruments available in Mexico for transnational evidence gathering are almost entirely treaty-based. There are no constitutional provisions which refer to transnational cooperation aside from Article 119, which deals with extradition. Similarly, the Federal Code of Criminal Procedure has only three articles that deal with this matter.

Article 58 mentions that federal courts which require foreign assistance must first go before the Supreme Court which will in turn ask the embassies to carry out the request.¹ Article 59 states that the request may be channelled through the secretaries at the embassies or the consular agents.² Article 60 requires foreign courts seeking assistance to comply with the all legal requirements including those found in treaties.³

These articles also provide rules regarding the legalization of signatures of court officials or diplomats, but nothing more is forest out. Despite the fact that Article 60 implies that there are laws which provide for different requirements and formalities which need to be carried out before a request can be sent abroad, there are no other provisions, at least not at the federal level.⁴ Consequently, the legal framework heavily relies on international treaties.⁵

The codes of criminal procedure which will bring in the adversarial procedure in Mexico will also have an impact on transnational inquiries. The constitutional provisions are already in place, but it is now necessary to adjust the codes of criminal procedure. This has brought about a series of model codes of criminal procedure which may be used by the states in their reform process. Two of these have been especially influential. There is the Model Code of the Adversarial Criminal Procedure for the States and the project of a Federal Code of Criminal Procedure.

None of these include sweeping changes specifically in the field of transnational cooperation, but there are some interesting propositions. Both codes remove the requirement to go before the Supreme Court when a lower tribunal needs assistance from abroad. While the Model Code does not specify a particular procedure, simply referring to the treaties Mexico is a party to,⁶ the Federal Code mentions that the courts may ask the “diplomatic authorities” abroad directly.⁷

The Federal Code does have two clauses which merit some comments. First, it states that all requests from abroad must be translated if they are not in Spanish.⁸ This article may be at odds with those treaties which no longer require translations. The other interesting clause states that pre-trial measures, which may affect the rights of individuals (personally, on their property or rights generally), need to be approved by the courts, while other forms of assistance may be carried out without the courts approval.⁹ Again, this may be in violation of those treaties which do not require any special formalities. In both cases, the fact that treaties supersede federal law may make these paragraphs null and void.

This meagre national legal basis contrasts sharply with the amount of international treaties that Mexico is a party to. Currently there are 30 such bilateral treaties which regulate judicial assistance in criminal matters. Mexico is also a party to the IACMACM as the sole multiparty and regional treaty on these issues. However, 37 bilateral treaties have been signed which deal with specific crimes: 2 regarding tariff fraud, 2 dealing with organized crime and 33 with drug trafficking. Finally, 5 multilateral treaties dealing with specific crimes but with provisions on mutual assistance have been ratified, most notably the UN CTOC and the UN CITNDPS.

It is also interesting to point out that Mexico is party to only four bilateral conventions with members of the European Union: Spain, France, Portugal and Greece. On the other hand, Mexico has signed a bilateral treaty specifically on organized crime with Italy and treaties on drug trafficking with the United Kingdom, Italy, France, Spain and the European Council.

The amount of treaties to which Mexico is party may seem small in comparison to other States, but by contrast, just over 30 extradition treaties have been signed, contrasting sharply with those dealing with judicial assistance in criminal matters.

This legal structure has the following consequences. First, there are very few legal precedents that interpret matters of transnational cooperation. Secondly, legal literature regarding this matter is also very scarce.¹⁰ Thirdly, unless otherwise provided (presumably in a treaty), the national rules that govern evidence gathering apply regardless of the fact that the request originates from abroad. This includes most notably matters regarding fundamental rights and judicial review, in particular complying with the standards of the ACHR and its enforcement mechanisms.

This lack of regulations is also present in the administrative structure of the PGR which does not have a single centralized unit that deals with transnational cooperation. There is a General Directorate on Transnational Cooperation; however, it does not have powers to implement any of the international treaties or the law itself.¹¹ Similarly, the General Directorate on Extradition and Legal Assistance can only oversee compliance with international treaties that deal with transnational cooperation and aid the federal and state authorities in obtaining information from foreign authorities.¹² The closest administrative body that has investigative powers is the General Directorate on International Police Affairs, which serves as a liaison office with INTERPOL. However, according to the internal regulations, its investigative powers are limited to the location and retrieval of stolen vehicles, aircraft or vessels in conjunction with consular offices abroad.¹³ It also has powers to locate, retrieve and repatriate stolen pieces of art, including those with historical or archaeological value, also in coordination with consular offices abroad.¹⁴ This office also has the power to coordinate the federal, state and municipal police forces in order to comply with international obligations, regarding police work.¹⁵ Many forms of evidence gathering require police work when this General Directorate has some intervention power, but the actual cooperation is carried out by the federal, state or municipal authorities.

As seen above, there is no federal law that establishes any specific procedure regarding the transfer of evidence. Each treaty has peculiarities that must be observed. All treaties state that the PGR will be the Central Authority for the purposes of transferring evidence¹⁶ and, in particular, the General Directorate of Extradition and Legal Assistance will coordinate these petitions between the foreign and local authorities. Hence, when a Mexican authority is petitioned, the request must be address to the PGR, which in turn will forward it to the official that has jurisdiction over the matter. This official will then carry out the request in accordance with the international treaty. Conversely, when a federal or state court needs assistance from a foreign court, the PGR will carry out the request through the consular or diplomatic channels abroad. As seen above, in the case of federal courts, these need to address the request before the Supreme Court, who will, in turn, forward the request through the PGR.

The different international treaties usually specify the forms of cooperation which are available to the investigative or judicial authorities. As far as evidence is concerned, the most prominent deals with witness testimony, obtaining documents or carrying out search warrants (and transferring the evidence that may be found).¹⁷ Some treaties include gathering testimony from expert witnesses¹⁸ and judicial inspections.¹⁹

As far as witness testimony is concerned, some treaties provide for the transfer of persons who are already in custody, so that they may testify abroad. Treaties make it very clear that this only applies to potential witnesses that are already detained, for any number of reasons, such as awaiting trial or those who have already sentenced. These treaties also expressly point out that they do not extend to extraditions. This means that the people in custody may not be tried abroad since this would require a temporary extradition, which will obviously fall outside of the object of the treaty.

There are other forms of cooperation usually included in these treaties, such as pre-trial measures; and others which do not directly deal with transfer of evidence, such as summons, locating and identifying persons and exchange of information. Some treaties may include a general clause which permits any other form of assistance when there is mutual consent from the parties and it would not contravene the object and purpose of the treaty.²⁰ Other treaties may simply state that evidence may be obtained from abroad, without specifying the particular forms that may be requested.²¹

As for the requirements needed to execute the request, one might point out that the locus regit actum rule is the basis for collaboration. In the case of Mexico, the lack of precise regulation means that the request must not be illegal or unconstitutional. The most common formula simply states that the request may be refused if it is contrary to the requested State’s legal order, the treaty itself, or may harm its national security or public order.

The treaties to which Mexico is a Party usually detail the content of each request; however, there seems to be a trend that relaxes the formalities. One striking example is the bilateral treaty with France, which does not even require translations of the documents²² and even the possibility to forgo the Central Authorities allowing the requesting authority to address its counterpart directly. Indeed, more modern bilateral treaties expressly state that legalizing signatures of the functionaries and other such formalities are not necessary.

Along with the transfer of evidence, pre-trial measures are the most important forms of cooperation contained in the treaties Mexico is party. However, these also involve some standard clauses which are found in most mutual legal assistance treaties. These include seizures and freezing assets or property²³ or any form of temporary lien before or during trial on property.²⁴ Usually the property which is subject to these measures is objects, instruments or the proceeds of the crimes allegedly committed.²⁵ It is also important to note that these measures are also subject to the locus regit actum rule. This may be important in the field of organized crime, where Mexico has enacted asset recovery and domain extinction mechanisms which are not known in many other countries, so these requests may be denied.

It is important to note that none of the treaties to which Mexico is a party deals with the right to liberty, since this is a measure that is exclusive to the extradition process.²⁶ As mentioned above, some treaties even go so far as to expressly exclude extradition, meaning that any form of detention which is part of this process would automatically be excluded.²⁷

2.2 Special Regulation in the Field of Transnational Organized Crime

Mexico is a party to two bilateral treaties involving organized crime and the general UN CTOC. While both bilateral treaties deal with the exchange of information and intelligence gathering in general terms, the UN CTOC includes more specific forms of cooperation amongst States. In this regard, it is relevant to describe the national efforts to comply with these forms of cooperation. After listing all the forms of transnational assistance available to the State Party to the UN CTOC, Article 18(3)(i) contains a residual clause which allows for any form of cooperation not prohibited by the domestic law of the requested Party. This allows for cooperation using the special techniques provided by the Convention to investigate organized crime, such as confiscation,²⁸ the use of protected witnesses,²⁹ controlled delivery, electronic surveillance, and undercover operations.³⁰

The issue of electronic surveillance has been dealt with above; the Federal Constitution allows this technique to be used in the investigation of any crime, so it stands to reason that it may be used against transnational organized crime as well. On the other hand, there are some interesting features of confiscation and witness protection which merit some further explanation.

The UN CTOC has a complex scheme for confiscation, which includes its own article on international cooperation that does not pose any problem for its application in Mexico. However, it is relevant to establish the scope of the term “confiscation” in Mexico, because it may be relevant to the application of the UN CTOC. Article 2(g) defines this term as follows:

Confiscation, which includes forfeiture where applicable, shall mean the permanent deprivation of property by order of a court or other competent authority […].

This is a very broad definition which may include what in Mexico is called domain extinction (extinción de dominio).³¹ This may be similar to forfeiture in Common Law jurisdictions, however, at least one commentary suggests that forfeiture and confiscation are actually synonyms which do not differ in substance.³² In any event, the definition only requires a court order depriving an individual of its property rights. This would definitively include domain extinction, in which a court order is preceded by a trial in which an individual’s property is forfeited to the State based on his involvement with organized crime.³³ It must be made clear that this procedure is not criminal in nature, since it is carried out independently of the individual’s guilt in a criminal trial and it only affects the property rights of the individual, and any other personal rights are not affected.³⁴

The Federal Statute on Domain Extinction includes a chapter on international assistance. The Statute mentions that the international cooperation will be carried out through the treaties Mexico is a party to or on the basis of international reciprocity.³⁵ This may be problematic if the property sought is in a country that does not recognize this procedure. While the UN CTOC’s definition seems to allow the use of domain extinction, it still holds the possibility of international cooperation to the availability of this mechanism in the requested State.³⁶ This will also be true if international reciprocity is invoked, since it is unlikely that any State would comply with a measure that is completely unknown to them.

A foreign government may request Mexico to assist it in cases where the property sought is in Mexico. This needs to be carried out on the basis of a treaty or international reciprocity.³⁷ While no bilateral treaty or the UN CTOC consider carrying out a domain extinction sentence expressly, the residual clauses usually include will suffice. However, the Federal Statute states that when a foreign sentence needs to be carried out in Mexico, the foreign authorities need to petition the PGR, and then, on that basis, the PRG will petition the federal courts to carry out the trial.³⁸ This is truly an odd procedure since in essence it requires the Mexican authorities to start an entirely new trial, regardless of the fact that a foreign court may have already issued a sentence against the property sought in Mexico. It is hard to think of this as a form of international cooperation since this does not entail carrying out the foreign sentence, but instead the issuing of a new sentence by a national court. While this does not mean that the property will be given to the Mexican State authorities,³⁹ it seems to deny sentences derived from foreign courts any validity or recognition. On the other hand, this procedure seems to comply with the UN CTOC, which states that in the case of confiscation a requested State may “submit the request to its competent authorities for the purpose of obtaining an order of confiscation and, if such an order is granted, give effect to it; […].”⁴⁰ In other words, the requested State may carry out the procedures in domestic law necessary to obtain a confiscation order, which in the case of Mexico it entails starting a new trial and securing a different sentence.⁴¹

A less challenging issue is the matter of witness protection. The UN CTOC calls for assistance in relocating witnesses abroad for their protection.⁴² In this matter, it does not seem to be a problem since witness protection is afforded through the Federal Organized Crime Statute. So the residual clauses or the UN CTOC itself can be the legal basis for cooperation in the relocation of witnesses. Moreover, the scope of the Federal Statute is very broad since it includes the protection of judges, expert witnesses, victims or any other person that may need protection because of their role in the trial.⁴³ However, it leaves out relatives or other persons close to them if they do not personally take part in the trial. This exclusion is at odds with the UN CTOC which expressly includes these categories as part of any witness protection program.

3 Obtaining and Admissibility of Evidence and the Respect for Human Rights Guarantees

Some treaties that Mexico is a Party to have clauses pertaining to fundamental rights, but this is a generalization since others like the bilateral treaty with the United States does not mention any such matters. Commonly, the references to fundamental rights give the requested State the right to refuse cooperation when it deals with political crimes,⁴⁴ military crimes⁴⁵ or when the prosecution is based on discriminatory grounds.⁴⁶ Some treaties may also include prohibitions to cooperate when the death penalty or life imprisonment may be imposed or in violation of the double jeopardy prohibition.⁴⁷ Exceptionally, some treaties may include other prohibitions commonly found in extradition treaties such as the double criminality prohibition⁴⁸ or the minimum penalty requirement,⁴⁹ double jeopardy prohibition or a bar on the cooperation with ad hoc tribunals or in the prosecution of tax offences.⁵⁰

Some generic clauses can be found in certain treaties which give the right to the requested State to refuse assistance when this may violate “public order”⁵¹ or “international obligations.”⁵² These phrases may be linked to fundamental rights; hence, it could be argued that these require compliance with nationally and internationally recognized fundamental rights.

It is also important to mention that Mexico has adopted the practice of refusing private parties the use of these treaties to obtain evidence from abroad.⁵³ These provisions are problematic since they may contravene the equality of arms principle and the right to defense, both of which are enshrined in the Federal Constitution⁵⁴ and in the IACHR⁵⁵; however, this issue has not been challenged.

A different problem is how to challenge any fundamental rights violations. This involves two separate issues. Firstly, one must try to identify which constitutional right may be infringed, which would require an analysis of the due process provisions. Secondly, it is necessary to consider the writ of amparo, which is the judicial review available in Mexico.

There are several due process considerations that may be relevant.⁵⁶ While no treaty expressly authorizes assistance with regard to electronic surveillance or similar investigative methods, most treaties allow for any form of assistance permitted by national law.⁵⁷ This is the case with Mexico, where electronic surveillance is allowed, albeit with certain constitutional constraints. This may seem problematic because of the precise wording of the Federal Constitution which states that only the federal courts may authorize the use of electronic surveillance. Additionally, it says that this authorization may be issued by request from the state governments or the PRG.⁵⁸ A strict interpretation of these requirements may lead to the conclusion that a foreign authority may not issue any form of electronic surveillance to be used in Mexico nor a foreign government petition to the federal courts for such a measure.

As mentioned above, there is no direct precedent allowing the writ of amparo to proceed in matters of international assistance, so it is necessarily to look at cases derived from family law or assistance between Mexican federal states for guidance. In this context, the First Chamber of the Supreme Court had to resolve whether a request from a foreign state agent may be challenged, given that the Federal Constitution and the federal courts do not have jurisdiction over foreign state agents. The Chamber started by saying that no government action which may affect fundamental rights may go unchallenged.⁵⁹ Therefore, it had to find a way to address the territorial limitations of judicial review in Mexico. In doing so, the Chamber reasoned that although it had no jurisdiction over foreign state agents, it did have authority over their Mexican counterparts which actually execute the petitions from abroad.⁶⁰ These courts can be made responsible for not complying with the treaty or national law, including the Federal Constitution.⁶¹

After resolving this issue, the Chamber had to provide for a remedy if the petition was illegal. It resolved the matter by saying that if the foreign request were illegal or unconstitutional, the federal court, on judicial review, could bar the requested authority from complying with the requesting State.⁶²

It would make sense that if this reasoning applies to family law, it could also be used in criminal procedures, where fundamental rights are also at stake. Applying this reasoning to electronic surveillance in accordance with the Federal Constitution, the foreign authorities would have to petition the PGR for assistance in securing a warrant allowing for electronic surveillance. In turn, the Mexican state agent and the federal court which would grant the warrant would be subject to any constitutional challenge deriving from the request.

While the electronic surveillance scheme is particularly important because of its constitutional hierarchy, the Federal Constitution contains a clause excluding evidence obtained in violation of fundamental rights.⁶³ This provision may be used to challenge evidence requested abroad in violation of any due process provisions of the Federal Constitution, such as the requirement for a search warrant⁶⁴ or the prohibition against the use of torture.⁶⁵ Other due process rights which may be affected may also derive from international human rights law. The interplay with national law will be considered in the relevant section.

However, this constitutional exclusionary rule will probably be more relevant for evidence obtained from abroad, which will need to comply with the particular treaty used to obtain it, the national law of the requested State and fundamental rights, which include at a minimum those mentioned in the Federal Constitution.

There is one aspect of the newly established adversarial system which may be difficult to overcome. The Federal Constitution contains within its Bill of Rights the minimum standards for every criminal trial, which relies heavily on oral arguments brought before the judge.⁶⁶ Thus, the following are some of the due process provisions found in the Federal Constitution: the adjudicating judge must be present in every hearing,⁶⁷ only the evidence which is heard in the court will be admissible,⁶⁸ and all the parties involved must be present at every hearing.⁶⁹ These due process rights do not seem to take into account the need to take testimony from a person found abroad. This is especially relevant if the defendant cannot question the prosecutor’s witness. Compounded with the fact that many treaties bar private parties from using these conventions from obtaining evidence from abroad, the international scheme poses a risk to the equality of arms right. Other jurisdictions have solved this problem by making an exception to the hearsay prohibition,⁷⁰ but this issue has not been addressed in Mexico.

4 Cooperation with International Criminal Tribunals and the Protection of Fundamental Rights

4.1 Ad Hoc Tribunals

The relationship Mexico has with United-Nations-sponsored ad hoc Tribunals is complicated. Since the Federal Constitution has an express prohibition on special courts of any kind, it would stand to reason that the official position would be not to cooperate with these tribunals.⁷¹ However, some factors do point the other way.

The official position Mexico adopted during its presidency of the United Nations Security Council was to fully cooperate with the ICTY and the ICTR.⁷² Additionally, there is evidence that Mexico has indeed at least cooperated with the Yugoslav Tribunal. However, the form of assistance provided and the way it was carried out is unknown since this information is considered classified in accordance with Article 53 of the Rules of Procedure and Evidence of the international tribunal.⁷³

Despite the fact that Mexico has cooperated with the ICTY, invoking the non-disclosure clause of Article 53 leaves many questions unanswered. First, there appears to be no way of knowing what was requested from Mexico, from which case the request came from, and perhaps most importantly, what the legal basis was for such cooperation. This last matter seems important since Mexico never enacted legislation allowing its authorities to assist the ad hoc Tribunals. One might argue that the statutes of these tribunals would be enough to provide a legal basis for cooperation; however, the legal recognition of Security Council resolutions in domestic law is questionable, let alone of other legal documents such as the Rules of Procedure and Evidence.

With this information, it is difficult to assess whether Mexico has complied with fundamental rights in its cooperation with the ICTY in the particular instances where assistance has been requested. However, it is plainly obvious that if there is no legal basis for such cooperation, at least the legality of these measures may be called into question.

4.2 International Criminal Court

The relationship between the ICC and Mexico is also complex. The debates over the constitutionality of the permanent court were very intense⁷⁴ and they actually ended with a constitutional amendment which in essence made it possible for the President and the Senate to ratify the Rome Statute.⁷⁵ Although the political problem was solved, the legal difficulties have only begun. The Constitutional amendment states:

The Federal Executive may, with the Senate’s approval in each case, recognize the jurisdiction of the International Criminal Court.⁷⁶

It is obvious that this clause creates many obstacles with regard to cooperation with the ICC. The picture will be clearer once the statute, which implements the mechanisms for cooperation, is enacted. With the limited information available it is easy to conclude that the general obligation to cooperate with the ICC is far from self-evident,⁷⁷ since it would depend on the decision of the Executive and Legislative whether to comply with the international obligations derived from the Rome Statute.

There are some issues that need to be addressed by the implementing legislation, which may qualify the sweeping constitutional text. Amongst the most important aspects is the meaning of the words “case” and “jurisdiction”, and consequently the concrete circumstances where approval may be necessary. This will better define the extent to which Mexico will collaborate with the ICC and the potential risk of breach of its international obligations.

Despite the potential noncompliance with the Rome Statute and the lack of implementing legislation, Mexico has already addressed requests for cooperation from the ICC without the approval of the Executive and the Senate. As with the ad hoc Tribunals, the Mexican government has classified all documents related to requests from the ICC on the basis of Article 87(3) of the Rome Statute. Consequently, the same conclusions may be reached as in the previous section.⁷⁸

While it is clear that Mexico has complied with its international obligation to cooperate with the ICC (despite the aforementioned constitutional provision), it is impossible to know at this point the details of any requests and the answers given by the government. This may entail a breach of fundamental rights, at least with regard to the legality of the actions taken in proceeding with the request, but it may have also breached the Federal Constitution insofar as no authorization was given by the Executive and the Senate.

At present, the statute enabling cooperation with the International Criminal Court Act has already been passed by the Senate and is now before the House of Deputies.

Perhaps the most important part of this statute is that it attempts to restrict the scope of the Federal Constitution which drastically limits the capacity of Mexico to comply with its international obligations, as discussed above. This is attempted by defining what it is meant by “case” and “jurisdiction” in the constitutional text. Hence, Article 10 defines “case” as any likely criminal conduct which may fall within the jurisdiction of Mexican courts. Additionally, “jurisdiction” is defined as any procedure which takes place after the ICC has authorized the Prosecutor to initiate an investigation.⁷⁹ Thus, the Executive and Senate’s approval of the ICC jurisdiction would only be needed when Mexico or Mexican nationals are deemed directly affected. This still leave a wide range of cases where there might be a breach of international obligations.

The rest of the proposed statute falls in line with the requirements of the Rome Statute. There are some clauses which may be troublesome because they include exceptions to the cooperation obligations. A request for cooperation may be refused if it breaches any due process rights (formalidades esenciales del procedimiento),⁸⁰ if there is a risk to the life, security of health of any person,⁸¹ or if there is a risk to national security. These objections would be subject to consultations before the ICC,⁸² which is a negotiating procedure allowed by the Rome Statute to reconcile national interests with international obligations.⁸³ Consequently, this conciliatory procedure would presumably solve any discrepancy.

4.3 The Influence of Supranational Case-Law on the Domestic Law in the Protection of Fundamental Rights

In Mexico, the relationship between domestic law and international law, including international human rights law, is going through some interesting changes. The beginning of the discussion is Article 133 of the Federal Constitution, which states that treaties are part of domestic law. It further states that judges, both at the federal and state level, must use international treaties to guide their decisions.⁸⁴ Thus, treaties are considered self-executing where it is possible to do so without implementing legislation.⁸⁵ Since there is no distinction between which types of treaties are part of the national legal system, only providing that they go through the ratification process, the range goes from human rights conventions such as the ACHR to extradition and mutual assistance treaties.

Additionally, the Supreme Court has stated that there is a legal hierarchy that places treaties above federal and state law and subject only to constitutional provisions.⁸⁶ At the time of this ruling, the position of the High Court was considered very important because from the plain reading of the Federal Constitution it could be argued that federal law and treaties had the same hierarchy. This holding has actually opened the floodgates for a judicial acceptance of International Law as a whole, including customary international law⁸⁷ and the frequent use of General Assembly Resolutions in cases where it is necessary to determine the scope of children’s rights,⁸⁸ and rules of interpretation such as the pro persona standard.⁸⁹

Despite making treaties subject to the Federal Constitution in the very case mentioned above, the Supreme Court left open the possibility that human rights treaties could have constitutional hierarchy.⁹⁰ The High Court, hinted that there may be an exception with regard to human rights treaties in a case involving the use of force by police agents.⁹¹ This trend has been followed by lower federal courts who have accepted that human rights treaties have constitutional hierarchy⁹² and may even declare that a national law or act of government is void because it contravenes international human rights treaties, primarily the ACHR.⁹³ With supranational case-law, the situation is similar. There has been a gradual acceptance of case-law from the IACtHR. Most recently, the First Chamber of the Supreme Court has declared that the use of case-law of the Inter-American Court on Human Rights by all tribunals is compulsory.⁹⁴

While there is no case where the courts have actually used supranational case-law in situations of transnational inquiries, there is no reason to think that this trend will constitute an exception to these circumstances. Insofar as transnational inquiries are linked to the due process provisions of the ACHR and the relevant case-law, these standards are also applicable.⁹⁵