2008] The Minimum Core of Economic and Social Rights 145 Consensus renders legitimate the coercion implicit in law by helping to ensure the sovereign equality of all states (i n international law) or the equal participation of all citi zens (in constitutional law) in the agreement to be bound by laws.180 The importance of consensus in inte rnational law is evidenced in the voluntarist structure of bo th treaties and customar y international law. For general treaty regimes, co nsent precedes ratification and t he acceptance of obligation. 181 It also justifies the practice of allowing (certain) treaty reservations and a “margin of appreciat ion” to constrain the application of international law in domest ic legal systems. For cust omary international law, consensus is als o a foundational feature. The positive sources of cus tomary international law—opinio juris and state practice— are important precisely because they are proxies for consent, even if expressed tacitly.182 In permitting exceptions, custom again gives prior ity to cons ent, precluding customary law’s application to persistently objecting states. Nonetheless, the centrality of consens us shifts with respect to human rights. For both treaty-based and customary human right s norms, the norm of consensus is secondary to the high er moral goals suggested by these conventions. For the oblig ations which flow from th ese moral goals, consent 183 For example, whil e states’ may be both constitutive and destructive. ratifications are required in order to establish obligations, the principal human rights treaties are pur portedly universal in scope and there are limits to the reservations that countries can make in bec oming parties. 184 Many commentators argue that consensus should not count for human rights as it does for other obligat ions, because human righ ts treaties have been established to protect minorities. 185 Similarly, the peremptory norms of custom, which rely on a normative rather than co nsensus-based hierarchy, are (presenting the higher agreem ent expressed during “const itutional moments” as key to understanding constitutional self-restraint and judicial review). 180. Neuman, supra note 15, at 1864-65 (noti ng the parallel operati on of consensus across constitutional and international human rights law). 181. Vienna Convention on the Law of Treatie s, May 23, 1969, 1155 U.N.T.S. 331, 8 I.L.M. 679. 182. Statute of the International Court of Justice, art. 38(1)(b), June 26, 1945, 59 Stat. 1055, 33 U.N.T.S. 993 (referring to “international custom, as evidence of a general practice accepted as law”). See also BROWNLIE, supra note 178, at 4-11, and cases cited therein. 183. Martti Koskenniemi, The Fate of Public Internati onal Law: Between Technique and Politics, 70 M ODERN L. REV. 1, 4-5 (2007) (citing Belilos v. Switzerland, 132 Eur. Ct. H.R. 28, 60 (1988)) (demonstrating a trend whereby human rights organs give special priority to hum an rights treaties over formal State consent). 184. Reservations to the C onvention on the Pr evention and Punishm ent of the Crim e of Genocide, Advisory Opinion, 1951 I.C.J. 15, 24 (May 28) (ruling, in response to reservations attached to the Genocide Convention, that the “ object and purpose of the Convention . . . lim it . . . the freedom of making reservations”). The doctrine of invalid reservations would seem to detract from norms of consent, but see Ryan Goodm an, Human Rights Treaties, Invalid Re servations, and State Consent , 96 AM. J. INT’L L. 531 (2002), who suggests that severing invali d reservations may maximize, rather than obstruct, state consent. 185. See, e.g., Eyal Benvenisti, Margin of Appreciation, Cons ensus, and Universal Standards , 31 N.Y.U. J. INT'L L. & POL. 843, 850-53 (1999) (criticizing the us e of consensus theories in hum an rights).