The OHCHR's Recommended Principles and Guidelines on Human Rights and Human Trafficking, under Principle 2, affirm State's legal responsibility to act with due diligence to prevent, investigate and prosecute instances of trafficking in persons, as well as provide assistance and protection to victims of trafficking. Attribution of responsibility to States can be complex, particularly where the breaching act is carried out by private actors rather than the State itself (which is often the case in the context of trafficking). In such cases, States may be responsible for their failure to act with due diligence to prevent, investigate or prosecute, rather than the act causing harm itself. Where that act itself is attributable to the State, examples may include: corruption of the judiciary through bribery or "direct involvement of public officials in trafficking through protection or patronage of commercial premises using the services of victims of trafficking" (for other examples and further, detailed, explanation of State responsibility, see Gallagher 2010, chapter four).
Under the standard of "due diligence", a State is obliged to exercise a measure of care in preventing and responding to acts by private entities that interfere with established rights. Failure to prevent an anticipated human rights abuse by a private individual or entity will therefore invoke the responsibility of the State. Similarly, legal responsibility will arise when the State fails to remedy abuses or violations of international human rights law, not only because access to remedies is of itself an established right …, but also because failure by the State to provide remedies in cases involving non-State interference with rights is a breach of the standard of due diligence. In other words, liability arises where the State could have made the situation better for the victim but failed to do so (p 77).
States responsibility to prevent breaches of international obligations have been discussed in a number of legal decisions. The V elásquez Rodríguez decision, a 1988 ruling by the Inter-American Court of Human Rights, discussed the responsibility of States for acts by private entities (see also Obokata 2006, discussing State responsibility).
"The State has [under article 1 of the American Convention] a legal duty to take reasonable steps to prevent human rights violations and to use the means at its disposal to carry out a serious investigation of violations committed within its jurisdiction, to identify those responsible, to impose the appropriate punishment and to ensure the victim adequate compensation" (para 174)
In the case of Rantsev v Cyprus and Russia, the European Court of Human Rights considered the responsibility of States to take appropriate measures to remove individuals from situations where they are at risk of trafficking. In that case, the Court held that "in order for a positive obligation to take operational measures [such as to protect] to arise in the circumstances of a particular case, it must be demonstrated that the State authorities were aware, or ought to have been aware, of circumstances giving rise to a credible suspicion that an identified individual had been, or was at real and immediate risk of being, trafficked or exploited within the meaning of article 3(a) of the [Protocol against Trafficking in Persons]" (para 286).
In Rantsev v Cyprus and Russia, the European Court of Human Rights affirmed that if State authorities were aware, or ought to have been aware, of a risk of trafficking, a failure to take appropriate measures within the scope of their powers to remove the individual from that situation or risk is a violation of that person's rights and, consequently, a breach of the State's positive obligations. The Court emphasized the need for such investigations to be full and effective: covering all aspects of trafficking allegations, from recruitment to exploitation. It further noted that these positive obligations applied to the various States potentially involved in human trafficking-States of origin, States of transit and States of destination. The Court affirmed that States are required to "take such steps as are necessary and available in order to secure relevant evidence, whether or not it is located in the territory of the investigating State" and that "in addition to the obligation to conduct a domestic investigation into events occurring on their own territories, member States are also subject to a duty in cross-border trafficking cases to cooperate effectively with the relevant authorities of other States concerned in the investigation of events which occurred outside their territories".
This court case was particularly important in clarifying the substantive content of several important legal obligations, including the obligation to prevent trafficking-related exploitation and the obligation to investigate cases of trafficking with due diligence.