  The sense and force of these questions, and the main features of the kind of answer given by natural law theories, can be given a preliminary indication. On the one hand, natural law theory holds that law’s “source-based character”—its dependence upon social facts such as legislation, custom or judicially established precedents—is a fundamental and primary element in “law’s capacity to advance the common good, to secure human rights, or to govern with integrity” (cf. Green and Adams 2019). On the other hand (cf. Green 2003), the question “whether law is of its very nature morally problematic” has from the outset been the subject of consideration by leaders of the tradition. (The first issue that Aquinas takes up about human law in his set-piece discussion of law, Summa Theologiae, I-II, q. 95 a. 1, is whether human law [positive law] is beneficial—might we not do better with exhortations and warnings, or with judges appointed simply to “do justice”, or with wise leaders ruling as they see fit? And see I.3 below.)  Classic and leading contemporary texts of natural law theory treat law as morally problematic, understanding it as a normally indispensable instrument of great good but one that readily becomes an instrument of great evil unless its authors steadily and vigilantly make it good by recognizing and fulfilling their moral duties to do so, both in settling the content of its rules and principles and in the procedures and institutions by which they make and administer it. Natural law theories all understand law as a remedy against the great evils of, on the one side anarchy (lawlessness), and on the other side tyranny. And one of tyranny’s characteristic forms is the co-optation of law to deploy it as a mask for fundamentally lawless decisions cloaked in the forms of law and legality.