3.1 Aspiration

Due diligence obligations in international law always include an aspirational element: its norm addressee is required to take appropriate measures because a certain regulatory end-goal is important and needs to be protected or improved. As such, the norm addressee of a due diligence obligation is expected to aspire to a higher level of performance. ^{Footnote 25} In terms of human rights protection in international human rights law, the aspirational aspect of due diligence obligations always implies the guarantee of a minimum degree of protection. Essentially, while the due diligence obligation strives for a high level of performance, it also ensures that there is a minimum level of protection that must be provided. It follows that while there is a basic level of protection that should be guaranteed, states are encouraged to go beyond this minimum requirement and to strive for a higher level of performance to better protect and promote human rights. But at the very least, a state has a duty to establish and apply an adequate legal framework affording human rights protection. This also includes protection from ill-treatment by non-state actors. The basic tenet of the duty to regulate is that states should regulate non-state actors to ensure human rights protection. ^{Footnote 26} A state that failed to do so would not be acting diligently.

Having emphasized the duty to regulate for nearly 30 years, the ECtHR is well aware of this duty. For example, in Costello Roberts v. United Kingdom, ^{Footnote 27} the Court found that the United Kingdom’s failure to protect the children by effectively enacting laws to criminalize the use of corporal punishment against children by private schools violated Article 3 ECHR. In terms of regulation, the ECtHR noted that ‘the State cannot absolve itself from responsibility by delegating its obligations to private bodies or individuals’, ^{Footnote 28} which ensures that states cannot delegate their legal human rights responsibilities along with the delegation of public tasks to non-state actors. ^{Footnote 29} Also interesting is the partly concurring, partly dissenting opinion by Judges Pinto de Albuquerque and Harutyunyan in Fernandes de Oliveira v. Portugal, which concerned the suicide of an individual in a private hospital. ^{Footnote 30} Albuquerque and Harutyunuan reiterated states’ obligation to ‘make regulations compelling hospitals, whether public or private, to adopt appropriate measures for the protection of their patient’s lives’. ^{Footnote 31} Another case worth mentioning is the case of Fadeyeva v. Russia, ^{Footnote 32} involving a state failure to regulate a non-state actor. A family living near a private steel plant argued that the pollution from the plant interfered with their right to private and family life under Article 8 ECHR. The ECtHR held that the Russian State had a positive obligation to regulate the private industry ^{Footnote 33} and to approach the problem with due diligence. ^{Footnote 34} According to the Court, in this specific instance the state was required to ensure that Ms. Fadeyeva and her family were resettled to housing outside of the area affected by the pollution. In rendering its judgment, the Court stated that the ‘steel plant was not owned, controlled, or operated by the State’, but that ‘the State’s responsibility in environmental cases may arise from a failure to regulate private industry’. ^{Footnote 35} Clearly, states are expected to establish some form of minimal regulation in the context of relations between individuals. ^{Footnote 36}

The IACtHR appears to take a similar approach. In one of the first cases where the IACtHR discussed the due diligence obligation of Article 1(1) American Convention on Human Rights (ACHR), the Court already expressed that states need ‘to organize the governmental apparatus and, in general, all the structures through which public power is exercised, so that they are capable of juridically ensuring the free and full enjoyment of human rights’. ^{Footnote 37} More concretely, this means that states need to prevent, investigate and punish human rights violations under the Convention, and attempt to restore human rights violated and provide compensation for damages caused by such violations. ^{Footnote 38} Another example where the IACtHR highlighted the obligation of states to regulate and monitor human rights is Juridical Condition and Rights of Undocumented Migrants. In its Advisory Opinion, the IACtHR made the link between ‘the obligation to respect and ensure human rights’ and the relations between individuals, extending the obligation to these relationships. ^{Footnote 39} A similar logic was followed by the San José Court in Ximenes-Lopes v. Brazil. ^{Footnote 40} In this case, the IACtHR explained that:

Reference can also be made to recent case law by the IACtHR confirming the duty of states to regulate, supervise and monitor conduct of third parties by establishing a governmental apparatus that ensures human rights protection. ^{Footnote 42}

3.2 Discretion in implementation

Both the ECtHR and IACtHR appear to highlight the efforts of states to establish a legal framework that regulates and supervises the relations between individuals. A prevalent concern, nevertheless, is that states are not provided any concrete direction as to how to realize such a framework. This is because regulating the behaviour of individuals is a challenging task on the international level; regulating this by means of specific rules might ‘cut against the grain’ of state sovereignty. ^{Footnote 43} Against this backdrop, states have discretion when it comes to its implementation. ^{Footnote 44} From a regulatory perspective, this entails that a state is expected to create more concrete and specific rules to ensure human rights protection. ^{Footnote 45} Put differently, a state needs to establish at the minimum a regulatory framework to guarantee human rights protection, yet what exactly this framework would look like seems to fall within the discretion of the states themselves.

In this regard, the ECtHR has famously adopted the doctrine of the margin of appreciation to address the discretion of states in terms of implementing the required minimum level of human rights protection. ^{Footnote 46} The margin of appreciation is flexible in that it takes into consideration the minimum standard of human rights protection that is to be provided by state authorities while, at the same time, a degree of discretion is given to states to accommodate their unique characteristics. ^{Footnote 47} In the end, the ECHR system lacks an absolute uniform implementation of human rights law, but instead calls for the adaptation of multiple specificities of a state, such as its history, political, social and cultural aspects. ^{Footnote 48} The rationale here is that states are in a better position to appraise which measures are to be taken. ^{Footnote 49}

In the context of Article 8 ECHR (family life, private life, and correspondence), the margin of appreciation is also referred to in giving states discretion in realizing human rights protection against conduct by non-state actors. For instance, in R.B. v. Hungary the ECtHR made it clear that states ‘enjoy a wide margin of appreciation in determining the steps to be taken to ensure compliance with the Convention with due regard to the needs and resources of the community and of individuals’. ^{Footnote 50} However, the Court also explained that the positive obligations related to Article 8 ECHR required a higher standard of states to respond to ‘alleged bias-motivated incidents’. ^{Footnote 51} In the assessment of the due diligence performance of the state, the Court concluded that the criminal law mechanisms implemented were defective to the degree that it violated the state’s positive obligations under Article 8 ECHR. ^{Footnote 52} Put differently, the state had a wide margin of appreciation, but since it failed to fulfil the minimum standard of human rights protection under Article 8 it violated the Convention.

In other cases, the importance of a specific right itself has appeared to influence the matter of discretion given to states. For instance, in terms of the right to life the ECtHR has held that a state is obliged ‘to do everything within [its] power’ to protect this right, whereas the obligation to protect the right to a peaceful enjoyment of possessions (a non-absolute right) ‘cannot extend further than what is reasonable in the circumstances’. ^{Footnote 53} Further, although states are not expected to protect all individuals from torture at all times, as this would impose an ‘excessive burden’ on authorities, they are expected to ‘at least’ provide effective protection for vulnerable persons and to take ‘reasonable steps to prevent ill-treatment of which the authorities had or ought to have had knowledge’. ^{Footnote 54} Connected to this, the Court moved on and asserted that the state enjoys a broader margin of appreciation in deciding what measures to take to protect individuals’ right to the peaceful enjoyment of possessions than they do in deciding how to protect the right to life.

Similar to the ECtHR, the IACtHR seems to endorse the idea of the margin of appreciation. ^{Footnote 55} As indicated by Duhaime, ‘the Inter-American institutions have referred to the [doctrine of the margin of appreciation] or some other form of recognition of deference towards States’. ^{Footnote 56} However, the Court follows a more cautious approach. ^{Footnote 57} Especially in cases where non-state actors have interfered with human rights, it is difficult to determine whether the Inter-American Court has developed a coherent doctrine on the matter. A possible reason for this is the historic context of the Inter-American human rights system, where the IACtHR has dealt with many cases of enforced disappearances. If the Inter-American institutions had given domestic courts discretion, hardly any state would have ever been condemned. ^{Footnote 58}

Although the IACtHR has been very careful in using the doctrine, there have been voices for more support of the doctrine in the Inter-American context these days. ^{Footnote 59} One argument is that the contemporary political and social context in which international human rights law operates in the Inter-American region is not the same as that of two or three decades ago. ^{Footnote 60} Follesdal also sees potential in adopting the doctrine of the margin of appreciation in the Inter-American system. Although critics may argue that the doctrine is inappropriate due to the less ‘democratic’ states in the region, the ‘democratic quality’ between the state parties to the ECHR and those to the IACHR is not so different. ^{Footnote 61} With that in mind, the way in which the ECtHR has applied the margin of appreciation to less democratic states may be relevant for the IACtHR. Moreover, the invocation of a margin of appreciation may ‘nudge’ states to perform a fair balance test themselves, which could promote democratic liberation and the independence of the judiciary. ^{Footnote 62}

3.3 Good faith

Good faith comprises a core element of due diligence obligations. ^{Footnote 63} After all, a state is not considered diligent if it acts in bad faith or knowingly refuses to take any measures to protect human rights. ^{Footnote 64} From a regulatory perspective, this means that good faith is necessary to ensure that states actively fulfil their obligations and achieve the intended regulatory goals. This becomes particularly apparent from the regulatory idea that the norm addressee of a due diligence obligation is persuaded to take measures in such a manner that its regulatory aim shall be achieved. In some branches of international law, this is realized via reporting norms that push the duty-bearer of a due diligence obligation to reach the aspiration or regulatory end-goal by taking action. However, not every branch of international law contains such norms. ^{Footnote 65} In such cases, the due diligence obligation needs to be read against the backdrop of good faith. The underlying rationale is that states are required to ‘perform their obligations with the genuine intention to achieve a positive result’. ^{Footnote 66} This is not merely a moral expression, but also a legal one, as it forms the foundational baseline structure of obligations deriving from the sources of international law. ^{Footnote 67} Without the notion of good faith persuading states to take action, a due diligence obligation would only require states to ‘try and do something’ within the scope of the discretionary powers they have. In such a scenario, states would not be pushed by law to reach the aimed aspiration of the obligation. ^{Footnote 68} The notion of good faith, therefore, fills up this gap and ‘deploys a certain kind of constitutional quality within the international law scheme and beyond that is conceived to be the very foundation of all law’. ^{Footnote 69}

In the context of the ECHR, its human rights system is based on the discretion that states have and the rather subsidiary function that the ECtHR has. ^{Footnote 70} Due to the diversity of state parties to the ECHR, the social field that is to be supervised by the ECtHR is particularly diverse. As indicated earlier, states have discretion in terms of implementation and the underlying rationale is that realizing the required efforts of states as regards human rights protection under the ECHR heavily depends on the mandate and consent of member states. ^{Footnote 71} Continuing co-operation is, without a doubt, important to realize an adequate level of human rights protection amongst the state parties. The Strasbourg Court has been aware of this in that the enforcement of its judgments fundamentally rely on the good faith of the states. ^{Footnote 72} Domestic authorities, therefore, are required to take the discretion they have seriously by implementing the ECHR with the genuine intention to protect human rights. In doing so, the notion of good faith pushes the member states to take action in light of protecting human rights.

In contrast to the ECtHR, the IACtHR appears to follow a more maximalist approach. In the landmark case Almonacid Arellano v. Chile, the IACtHR revealed a doctrine that the members of the IACtHR had been ‘waltzing’ with for some time, namely the doctrine of constitutionality control. ^{Footnote 73} This doctrine, which also has been qualified as ‘a genuine constitutional big bang’, ^{Footnote 74} refers to the obligation of public authorities of all state parties to the ACHR to set aside domestic laws that are in conflict with the Convention and interpretations of the IACtHR. ^{Footnote 75} Some argue that the basis for the constitutionality control doctrine is Article 2 ACHR, ^{Footnote 76} while others refer to pacta sunt servanda. ^{Footnote 77}

From a regulatory perspective, the constitutionality control doctrine may be praised in terms of advancing regional human rights. The doctrine significantly supplements the general due diligence obligation to protect human rights, and strongly persuades states to take action and realize human rights protection. Nonetheless, it has received profound criticism. ^{Footnote 78} As Contesse notes, the IACtHR failed, for instance, to sufficiently take into account the realities of different models of judicial review in its member states. ^{Footnote 79} According to the constitutionality control doctrine, a domestic judge shall have to follow the Inter-American Court and review a domestic law. This leads to a paradoxical situation for domestic judges. In some domestic legal systems, not all judges have power of judicial review. In Chile, for instance, only one single specialized court possesses the power to review domestic laws, but at the same time, it is obliged by the doctrine of constitutionality to set aside a domestic law if it contravenes the ACHR. To make matters even more complex, some states – like Colombia – use a mixed system where the powers of judicial review are shared between the Constitutional Court and district judges. ^{Footnote 80} In later case law, the IACtHR has added slight adjustments to the doctrine of constitutionality in that ‘organs of the Judiciary’ must apply the doctrine ‘evidently in the context of their respective spheres of competence and the corresponding procedural regulations’. ^{Footnote 81} However, this still did not solve the issue of the IACtHR overthrowing domestic legal standards in those states where courts of first instance have no power to review a domestic law at all. In the light of this, some authors have proposed models of making the constitutionality control doctrine more compatible, yet various attempts to make sense of the doctrine have been unsuccessful. ^{Footnote 82} Others have proposed alternatives of a more subtle approach of judicial dialogue between the IACtHR and domestic courts. ^{Footnote 83} Perhaps employing the notion of good faith in a less maximalist and supreme manner would suffice. This remains an open question.

4.1 Knowledge or foreseeability

As emphasized by multiple authors, knowledge is a crucial parameter that triggers a due diligence obligation. ^{Footnote 94} States can usually only be expected to perform due diligence if they have knowledge of a particular activity or potential risk. ^{Footnote 95} The ECtHR has acknowledged that the presence of actual knowledge may trigger a due diligence obligation. This knowledge may be determined by the adoption of legislation that addresses a particular harm or risk thereof, ^{Footnote 96} scientific research, ^{Footnote 97} national reports ^{Footnote 98} or history indicating potential harm. ^{Footnote 99} Further, the Strasbourg Court has repeatedly emphasized that states are not responsible for preventing all instances of human rights abuse caused by non-state actors but must take certain measures in circumstances where they ‘knew or ought to have known at the time of the existence of a real and immediate risk’ to an individual’s rights. ^{Footnote 100} The IACtHR also has illustrated that actual knowledge, if proven, can trigger a state’s due diligence obligation. ^{Footnote 101}

Human rights courts have also acknowledged that constructive knowledge may trigger a due diligence obligation. ^{Footnote 102} What matters is that a state ought to have known about a human rights violation or the risk thereof, not necessarily whether a state actually had specific prior knowledge. The ECtHR, in this respect, often refers to ‘knew or ought to have known’. ^{Footnote 103} A case in point here is the Court’s landmark ruling in Osman v. United Kingdom. ^{Footnote 104} The Court used the language of constructive knowledge, which it has repeatedly reiterated and which is comparable to standards found elsewhere in international human rights law. ^{Footnote 105} IACtHR case law also shows that constructive knowledge can trigger a due diligence obligation. For example, in Pueblo Bello Massacre v. Colombia the forced disappearance of 37 persons and an extrajudicial execution of 6 individuals was carried out by paramilitary groups with the acquiescence of state agents. Although no ‘specific prior knowledge’ by the state authorities was proved, it was irrelevant for the proceedings to establish the existence of such evidence since, according to the Court, ‘this could never condition the State’s obligation to provide protection’. ^{Footnote 106} As such, constructive knowledge appears to be a satisfactory requirement to trigger a due diligence obligation. ^{Footnote 107}

Both ECtHR and IACtHR case law also notably illustrate that the parameter of ‘knowledge or foreseeability’ operates in combination with the ‘proximity of a risk’. The language of the ECtHR suggests that a state will only be subject to an obligation under the Convention to take appropriate action when it either knew or ought to have known of a ‘real and immediate’ risk to an individual and does not take appropriate measures to remove them from the situation or risk. ^{Footnote 108} Similar to the ECtHR, the IACtHR assesses knowledge or foreseeability in relation to risk proximity. For instance, the existence of actual knowledge would only be relevant if the state is aware of an ‘imminent danger’. If the state would only be aware of an abstract danger, its failure to prevent the situation would not per se result in a violation. ^{Footnote 109} This also reflects the common observation that the obligation to protect is one of conduct and not of result. ^{Footnote 110}

This being said, the parameter of ‘knowledge or foreseeability’ appears to work in a non-binary manner and can have different degrees. In that way, it operates on a sliding-scale assessment against the backdrop of the reasonableness standard bonus pater familias. ^{Footnote 111} For instance, in Osman the Strasbourg Court used the foreseeability test, yet it held that the obligation to take operational measures must not ‘impose an impossible or disproportionate burden on the authorities’. ^{Footnote 112} In other words, the notion of reasonableness should guide the determination of measures a state can be expected to take. ^{Footnote 113} The IACtHR appears to follow a similar logic, but strikingly the IACtHR pays more attention to groups requiring some form of ‘special protection’ to determine when a situation or risk is reasonably foreseeable. For instance, foreseeability is earlier determined if the victims of human rights violations are members of a vulnerable group or in need of special protection, such as human rights defenders ^{Footnote 114} or vulnerable members of indigenous peoples. ^{Footnote 115}

4.2 Interests at stake

In terms of risk management, the specification of the protected rights and interests is important, as well as the vulnerability or special quality of the beneficiary of a state’s best-efforts performance. ^{Footnote 116} In that way, a state’s degree of expected efforts will be higher if the beneficiary of these efforts is more vulnerable. Examples include women, ^{Footnote 117} children ^{Footnote 118} or persons belonging to an indigenous community. ^{Footnote 119} At the same time, the context-specific nature of due diligence is very clearly evidenced in relation to the parameter of the interests at stake in a particular case. A state, for instance, cannot be responsible for all human rights violations committed between individuals within its jurisdiction because ‘the specific circumstances of the case and the execution of these guarantee obligations must be considered’. ^{Footnote 120} In the context of the European human rights system, there are two main aspects of this that can impact what is expected of states.

First, the existence of other obligations and interests, which must be balanced against the interests and rights at stake in the case. In this respect, the Court has made it clear that international human rights law does not require the state to violate other rules of international law to perform a particular due diligence standard and that, against the backdrop of bonus pater familias, competing interests and rights need to be balanced against one another. ^{Footnote 121} This was clearly stated in Ilaşcu and Others v. Moldova and Russia, where in the words of the Court: ‘[i]n determining the scope of a State’s positive obligations, regard must be had to the fair balance that has to be struck between the general interest and the interests of the individual’. ^{Footnote 122} The second aspect affecting the level of activity required by states is the nature of the right being claimed in a case (i.e., whether or not it is absolute) and the seriousness of the (potential) harm that an individual has/would suffer. In the ECtHR’s view, for example, ‘where there is evidence of patterns of violence and intolerance against an ethnic minority … the positive obligations incumbent require a higher standard of States to respond to alleged bias-motivated incidents’. ^{Footnote 123} On a more general basis, the Court has suggested that the seriousness of (risks of) harm caused by a non-state actor to an individual dictates to some extent the degree to which a state should involve itself to protect the individual. For instance, in Özgür Gündem v. Turkey the seriousness and widespread nature of attacks against a newspaper and its staff prompted the Court to find that the state’s reliance on investigations that had been ordered on a case-by-case basis by individual public prosecutors was not sufficient to fulfil the duty to ‘investigate and, where necessary, provide protection against unlawful acts involving violence’, especially given that the applicants had alleged that the authorities tolerated, if not supported, the campaign of which the attacks in question were part. ^{Footnote 124}

The IACtHR follows a similar logic. A good example can be found in The Environment and Human Rights. ^{Footnote 125} In this landmark Advisory Opinion, the IACtHR reaffirmed that the successful exercise of human rights depends on the existence of a healthy environment. States, in that respect, must take appropriate measures to prevent significant environmental harm to individuals. Nonetheless, measures that a state needs to take may be greater and different in the case of fragile ecosystems compared to those it needs to take to manage risks of damages to other components of the environment. The underlying reason for this is that fragile ecosystems have unique features and resources, and can impact global climate – making it more vital for a state to take measures. ^{Footnote 126} Therefore, the IACtHR follows the same general rule of thumb as the ECtHR: the more important an interest or right, the more necessary it becomes to take action. ^{Footnote 127}

Notably, non-derogable rights – such as the right to life – can have an important impact on a state’s performance to act with due diligence. Although states should ensure all human rights, in several cases, both the ECtHR and the IACtHR have emphasized the fundamental role of the right to life. For instance, in Opuz v. Turkey, the ECtHR determined that ‘in domestic violence cases perpetrators’ rights cannot supersede victims’ human rights to life and to physical and mental integrity’. ^{Footnote 128} Similarly, the Court holds it to be ‘especially necessary’ when dealing with absolute rights to determine whether (and to what extent) a minimum effort on behalf of the state to act to protect individuals was possible despite a state’s total or partial failure to act, and if indeed possible, whether that effort should have been made. ^{Footnote 129} In the same way, the IACtHR has pointed out that the right to life is an ‘essential corollary for realising other human rights’ and that states need to ‘adopt all the appropriate measures’ and must ‘adopt the necessary measures’ to realize sufficient protection of the right to life. ^{Footnote 130} Human rights courts, thus, regard the status and hierarchical rank of human rights as a serious one, leading to a heightened standard of care that is to be expected from a state, and less leeway to discharge its due diligence obligation. ^{Footnote 131}

4.3 Capacity of the state

As explained by Bartolini, early judicial practice in international law identifies the means at disposal for the state as a factor influencing a state’s due diligence performance. ^{Footnote 132} The underlying idea is that the performance of due diligence obligations is to be balanced in light of the available means for the state. With that in mind, it cannot be expected for a state to be responsible for omissions if it lacks, for instance, financial resources to mitigate and manage potential harm or the risks thereof. ^{Footnote 133} In respect of human rights protection, the ECtHR often interprets due diligence obligations as taking measures that are ‘at a State’s disposal’ ^{Footnote 134} and measures should not be applied in a way that would ‘impose a disproportionate burden on the authorities’ ^{Footnote 135} or ‘impose’ an excessive burden on the authorities’. ^{Footnote 136} A clear enunciation of the parameter capacity of the state was provided in CN v. United Kingdom. ^{Footnote 137} Here, the Court stated that in the face of knowledge or foreseeability of a state concerning a real and immediate risk to an identified individual, the state is under an obligation to ‘take appropriate measures within the scope of their powers’ to protect the individual. ^{Footnote 138} We see the notion of reasonableness coming back here, as the Court went on to note that ‘the difficulties involved in policing modern society’ should be considered and that ‘impossible’ burdens should not be imposed on authorities. ^{Footnote 139} It is thus clear that states are not expected to act outside of their capacity. ^{Footnote 140} The Court has been less instructive in laying down how the state’s capacity to protect an individual should be assessed, instead opting for a case-by-case approach dependent on the situation in/of a given state.

The IACtHR follows a similar line of thought. For instance, in González et al. (Cotton Field) v. Mexico, the Court held that:

A similar example can be found in Sawhoyamaxa Indigenous Community v. Paraguay where the state failed to ensure ancestral property rights of an indigenous community and its members, which affected their right to life. For the IACtHR it was clear that a state could not be responsible for every possible risk to the right to life. Operative choices, planning and adopting public policies, after all, have to be made by a state. In this respect, the obligations of the state must be understood in that it is not to be placed under a ‘disproportionate burden’. ^{Footnote 142} This indicates that the Court assesses the parameter of capacities against the backdrop of the overarching principle of bonus pater familias. The other side of the coin, however, is that the mere lack of resources cannot be used to completely discharge human rights responsibilities. ^{Footnote 143} The IACtHR also appears to make the link between the parameter of capacity of the state in the context of risk management and the duty to establish a governmental framework to regulate and supervise human rights. In the famous The Environment and Human Rights, the Court stated that although limited resources may exclude particular means, at the bare minimum a state is required to establish a proper governmental framework to meet the requirement of actual capacity. ^{Footnote 144} As this has to do with the establishment of a regulatory framework, it can be said that there is an overlap between the two paradigms of due diligence obligations.

4.4 Level of control

The final parameter that influences due diligence obligations has to do with the level of control exercised by states. It is essential to note that this parameter is a ground for a due diligence performance and something else than ‘jurisdiction’ or ‘control over the right holder’. ^{Footnote 145} The ‘level of control as a ground for due diligence’ is a common parameter for a due diligence performance, which is rather loose and operates in relation to the degree of care that is required to protect a particular interest or right. In other words, this level of control is connected to the source of the harm (or the risk thereof). It concerns the question whether the state has a particular level of control over the source of harm (or the risk thereof). ^{Footnote 146} The matter of ‘jurisdiction’ or ‘control over the right holder’, however, is something else and forms rather a unique condition for a due diligence obligation to arise in international human rights law. Other branches in international law do not require that the norm addressee of a due diligence obligation exercises control over the beneficiary of the best-efforts performance for that obligation to arise. Arguably, this has to do with the special character of due diligence obligations in international human rights law. ^{Footnote 147} In international human rights law, the condition of ‘jurisdiction’ or ‘control over the right holder’ requires a form of ‘control over the right holder’ that must be ‘effective’. In contrast, the ‘level of control over the source of the harm (or the risk thereof)’ as a parameter of a due diligence performance is rather loose and does not have to be effective per se. ^{Footnote 148}

When it comes to the ‘level of control over the source of the harm (or the risk thereof)’, ECtHR case law shows that this can have different dimensions: (i) control over an individual; or (ii) control over a certain subject matter. With regard to the state’s control over an individual, in its discussion of a possible violation of Article 5 ECHR in relation to enforced disappearances, the Court emphasized in El-Masri v. The Former Yugoslav Republic of Macedonia, that ‘[h]aving assumed control’ over an individual the State authorities have an obligation to account for the individual’s whereabouts and to ‘take effective measures to safeguard against the risk of disappearance and to conduct a prompt effective investigation into arguable claims that an individual has not been seen since allegedly being taken into custody’. ^{Footnote 149} While this case is quite a specific example, the Court’s wording suggests that the obligations are triggered whenever a state takes an individual into custody (i.e., assumes control over them). It is important to note, however, that this dimension applies to state authorities and not to situations of non-state actors infringing human rights of individuals.

The scope of states’ due diligence obligations can also be impacted by the control they have over a certain subject matter. If a matter falls under the regulation and control of a state, harm – including ‘accidents in this sphere’ – is brought within the state’s responsibility. However, responsibility for failure to protect human rights appears to be excluded when there is no control over a particular subject matter. ^{Footnote 150} Further, the parameter level of control is highly context-dependent and operates, similar to the other parameters, on a normative spectrum against the backdrop of the reasonableness standard, leading to a higher standard of care that is expected of states exercising a higher level of control. In other words, the more a state ‘supports’ or ‘tolerates’ the infringement of human rights, the more diligent measures a state needs to take.

IACtHR case law supports this proposition too. ^{Footnote 151} For instance, in Mapiripán Massacre v. Colombia, members of paramilitary groups committed a massacre without a dependent relationship between the state and the paramilitary groups. Although the state did not conduct the massacre itself directly, the Court noted that ‘the massacre could not have been prepared and carried out without the collaboration, acquiescence, and tolerance, expressed through several actions and omissions, of the Armed Forces of the State, including high officials of the latter’ and that the relevant acts by the paramilitary groups were attributable to the state ‘as they in fact acted in a situation and in areas that were under the control of the state’. ^{Footnote 152} After all, the massacre was planned several months in advance and carried out with full knowledge, logistic preparations, and collaboration by the state, enabling the groups to leave the areas under the control of the state and leaving the civilian population defenceless by transferring troops to other areas. ^{Footnote 153} Clearly, Colombia had control over the paramilitary groups and, without any preventive or protective measures set in place, it failed to protect the lives of the civilian population.

Nonetheless, states may have a ‘special obligation’ when they actively contribute to the creation of harm or the risk thereof, even if the state creates a regulatory framework to prohibit, prevent and punish human rights violations. This was acknowledged by the IACtHR in Ituango Massacres v. Colombia where members of the law enforcement and paramilitary groups robbed and killed unarmed civilians. After the Court admitted that there was a regulatory framework in place, it maintained that the state ‘objectively created a situation of danger for its inhabitants and did not adopt the necessary and sufficient measures to avoid … groups continuing to perpetrate acts such as those of the instant case’. ^{Footnote 154} Against this backdrop, Colombia was subjected to ‘special obligations of prevention in the zones where the paramilitary groups were present’. ^{Footnote 155}

Finally, a more complex scenario arises as for ‘control over domestic activities with extraterritorial effect’. ^{Footnote 156} In The Environment and Human Rights, the IACtHR was the first human rights court to address this matter by discussing a new extraterritorial jurisdiction based on control over domestic activities having a cross-border effect. ^{Footnote 157} As highlighted by Berkes, this opened the door for:

As such, the IACtHR seems to have expanded the extent of jurisdiction through causality. ^{Footnote 159} For instance, when a company in state A infringes the right to life of an individual in state B due to environmental pollution having a cross-border effect, the individual would fall under state A’s jurisdiction as long as the other parameters of the due diligence obligation are present in terms of the company’s behaviour. As jurisdiction depends on causality here, a strong link between the two is created. Violi also qualifies this as a legal state of affairs where ‘jurisdiction’ and ‘causality’ are seen as equals by the IACtHR. ^{Footnote 160} Although this novel construction of the jurisdictional link is at first sight very much welcomed in the context of environmental damage and human rights, the Court methodologically failed to describe the complicated relation between a state’s omission and extraterritorial consequences in this context. ^{Footnote 161}

Additionally, the IACtHR seems to be undermining the requirements for jurisdiction by considering a state’s control over the source of harm (or the risk thereof) as a key factor in fulfilling its due diligence obligations. This poses a problem as it disrupts the traditional understanding of how human rights obligations are established, questioning the normative relationship between those who hold rights and states who have a duty to uphold them. ^{Footnote 162} As we have noted before, it is important to distinguish between jurisdiction or control over the right holder and control over the source of harm or risk. However, the newly introduced extraterritorial jurisdictional link by the IACtHR seems to confuse ‘conditions of human rights obligations with those of due diligence’, ^{Footnote 163} hence blurring the lines between human rights obligations and the concept of due diligence.