CRC/GC/2003/5 page 6 III. RATIFICATION OF OTHER KEY INTERNATIONAL HUMAN RIGHTS INSTRUMENTS 17. As part of its consideration of general measures of implementation, and in the light of the principles of indivisibility and interdependence of human rights, the Committee consistently urges States parties, if they have not already done so, to ratify the two Optional Protocols to the Convention on the Rights of the Child (on the involvement of children in armed conflict and on the sale of children, child prostitution and child pornography) and the six other major international human rights instruments. During its dialogue with States parties the Committee often encourages them to consider ratifying other relevant international instruments. A non-exhaustive list of these instruments is annexed to the present general comment, which the Committee will update from time to time. IV. LEGISLATIVE MEASURES 18. The Committee believes a comprehensive review of all domestic legislation and related administrative guidance to ensure full compliance with the Convention is an obligation. Its experience in examining not only initial but now second and third periodic reports under the Convention suggests that the review process at the national level has, in most cases, been started, but needs to be more rigorous. The review needs to consider the Convention not only article by article, but also holistically, recognizing the interdependence and indivisibility of human rights. The review needs to be continuous rather than one-off, reviewing proposed as well as existing legislation. And while it is important that this review process should be built into the machinery of all relevant government departments, it is also advantageous to have independent review by, for example, parliamentary committees and hearings, national human rights institutions, NGOs, academics, affected children and young people and others. 19. States parties need to ensure, by all appropriate means, that the provisions of the Convention are given legal effect within their domestic legal systems. This remains a challenge in many States parties. Of particular importance is the need to clarify the extent of applicability of the Convention in States where the principle of “self-execution” applies and others where it is claimed that the Convention “has constitutional status” or has been incorporated into domestic law. 20. The Committee welcomes the incorporation of the Convention into domestic law, which is the traditional approach to the implementation of international human rights instruments in some but not all States. Incorporation should mean that the provisions of the Convention can be directly invoked before the courts and applied by national authorities and that the Convention will prevail where there is a conflict with domestic legislation or common practice. Incorporation by itself does not avoid the need to ensure that all relevant domestic law, including any local or customary law, is brought into compliance with the Convention. In case of any conflict in legislation, predominance should always be given to the Convention, in the light of article 27 of the Vienna Convention on the Law of Treaties. Where a State delegates powers to legislate to federated regional or territorial governments, it must also require these subsidiary governments to legislate within the framework of the Convention and to ensure effective implementation (see also paragraphs 40 et seq. below).