  Some writers defend a less austere version of this model, by weakening the notion of legal validity. They say that the validity of a norm needn’t depend solely on whether an institution has conveyed the norm but may further depend on certain moral conditions, provided such conditions are laid down by more fundamental institutionally created norms. For example, if the Constitution entrenches some values, the conditions of validity of norms created by ordinary legislation would include those values. In such a case, the values would play the crucial role only because some institution—a constitutional assembly—said so. In another variant, values may be made relevant to legal validity by the customary norm that governs judicial practice, which is the most fundamental norm, constitutive of a legal system. In that case, the nonnormative social fact of custom that constitutes the fundamental norm would make the values relevant to the validity of ordinary norms (Coleman 2001a). In all these cases, rights and obligations in law are explained ultimately by nonnormative social facts, but moral facts occupy some place further up in the order of explanation.