2008] The Minimum Core of Economic and Social Rights 155 separate phase of the Committee’s analysis of individual rights after the early 1990s. 237 These principles, which largel y respond to the “basic needs” inquiries of the Essence Approach, also add cult ural and environmental considerations. More to the point, they differ from the search for an essence by refusing to place these principles in a normative hierar chy. For example, the Committee’s General Comment on the right to food evades the question of whether the core content of the right relates to the “freedom from hunger” provision of the Covenant, or the br oader and more ex tensive right to 238 adequate food. A similar ambivalence attends the General Comment on the right to education, which does not suggest that primary education should be prioritized over higher educa tion within the minimum core. 239 Those who have utilized the operati onal principles suggest that their contribution lies in directing policy rather than law.240 In later comments, the Committe e departs from re ferencing the operational principles of availability, accessibility , and quality within the enumeration of “core obligations,” al though such principles figure as universally applicable to t he normative content of the right to the highest attainable standard of health and the right to water in the General Comments that set out to cl arify their content.241 Instead, the list of “core obligations” (appearing awkwardly alongside statemen ts of “general le gal obligations,” “specific legal obligations,” “int ernational legal obligations,” and “violations”) references several institutional obligations that require immediate performance. In the case of the right to health, the General Comment links the minimum core oblig ations to the declarations of international experts in health, popul ation, and devel opment, and to the mutually supporting rights of access to food, shelter, housing, sanitation, and potable water.242 Thus, for example, a “core obligation” flowing from the right to health is to provide essential drugs defined under the Worl d Health Organization (WHO) Action Pr ogramme on Essential Drugs;243 another is to implement a national public health strategy “on the basis of epi demiological 237. Chapman & Russell, supra note 225, at 10 (noting “a lapse of several years” in commentary on the content of rights). 238. Covenant, supra note 19, art. 11. F or an argument that freedom from hunger constitutes that minimum core of the right to food as im plied by General Comment No. 12, see Künnemann, supra note 66, at 83. For an argument from customary international law, see Smita Narula, The Right to Food: Holding Global Actors Accountable under International Law , 44 COLUM. J. TRANSNAT'L L. 691, 780-97 (2006). As a matter of custom, the right is applicable to the United States, despite its failure to ratify the Covenant, unless it can claim status as a persistently objecting state. 239. General Comment No. 13 , supra note 33, ¶ 57 (suggesting that the core includes both the provision of primary education and the adoption and implementation of “a national educational strategy which includes provision for secondary, higher and fundamental education”). 240. U.N. Econ. & Soc. Council [ECOSOC], Comm’n on Hum an Rights, Economic, Social and Cultural Rights: The Right of Everyone to the Enjoyment of the Highest Attainable Standard of Physical and Mental H ealth, ¶¶ 33-40, U.N. Doc. E/CN.4/2004/49/Add.1 (Mar. 1, 2004) ( prepared by Paul Hunt) [hereinafter ECOSOC, Right to Health] (contrasting organizational principles with the legal vocabulary of respect, protect, and fulfill). 241. General Comment No. 15, supra note 17, ¶ 12; General Comment No. 14, supra note 10, ¶ 12; see also General Comment No. 18, supra note 17, ¶ 12. 242. General Comment No. 14, supra note 10, ¶ 43. 243. Id. ¶ 43(d) (setting out the obligation “[t]o prov ide essential drugs, as f rom time to time defined under the WHO Action Programme on Essential Drugs”).