custody. They may prevent a victim from returning home until certain requirements, such as providing testimony against traffickers, have been met. The Trafficking Principles and Guidelines contain a specific reference to freedom of movement in the context of protecting established rights: States … should consider … protecting the right of all persons to freedom of movement and ensuring that anti-trafficking measures do not infringe upon this right (Guideline 1.5). When considering the human rights impact of a particular anti-trafficking measure, it is important to acknowledge that freedom of movement and related rights are not absolute. For example, under the terms of the International Covenant on Civil and Political Rights (art. 12 (1)), freedom of movement is only guaranteed, as a matter of law, to those who are lawfully within the territory of the relevant State. Freedom of movement and the right to leave can also be subject to lawful restrictions on the grounds of national security, public order, public health or morals, or the rights and freedom of others.144 This caveat could conceivably provide legal justification for restrictions on freedom of movement that aim, for example, to secure witnesses for a prosecution or to protect trafficked persons from retaliation and intimidation. Such claims would need to be tested on their merits. It would also be important to ascertain independently that the claimed restrictions do not separately violate other recognized rights, for example, International Covenant on Civil and Political Rights, article 12 (3). In relation to the right to leave one’s country, both the European Convention on Human Rights, article 3, and the American Convention on Human Rights, articles 22-23, provide that such restrictions must be “necessary in a democratic society”. The American Convention on Human Rights lists the scope of restrictions at article 30. 144 the prohibition on discrimination, explored in detail above.145 The Human Rights Committee, in considering the application of this exception, has noted that freedom of movement is “an indispensable condition for the free development of a person”.146 Any restrictions on this right “must be provided by law, must be necessary… and must be consistent with all other rights” (para. 11). The Committee has also noted that: Restrictive measures must conform to the principle of proportionality; they must be appropriate to achieve their protective function; they must be the least intrusive instrument amongst those which might achieve the desired result; and they must be proportionate to the interest to be protected… The principle of proportionality has to be respected not only in the law that frames the restrictions, but also by the administrative and judicial authorities in applying the law (paras. 14-15). In deciding whether a restriction on freedom of movement is lawful, it is therefore necessary to ask whether the relevant restriction is: (i) provided for by law; (ii) consistent with other rights (such as the prohibition on sex-based discrimination); and (iii) necessary to protect the individual concerned. These requirements must all be fulfilled. For example, even if a State is able to argue that its emigration restrictions are based on a need to preserve public order or public morals through preventing trafficking, and that the measures taken are both necessary and in proportion to their stated aim, that same State On the issue of compatibility between restrictions on freedom of movement and compatibility with other rights protected in the International Covenant on Civil and Political Rights, see Nowak, op. cit., pp. 273-274. 145 Human Rights Committee, general comment No. 27: Freedom of Movement, para. 1. 146 COMMENTARY 87