Thin and thick and the two-pillar test
Steven Ratner’s book measures international core norms against a standard of “thin justice”. That justice is thin, because it is less demanding than the standard we would use to judge domestic law and domestic institutions, “it is a justice that reflects the thinness of the community in which it operates” (p. 90, see also p. 416). The distinction between domestic thickness and international thinness is inspired by and parallels Michael Walzer’s thick and thin morality. Ratner does not espouse a radical cosmopolitanism which claims that the standards of justice need to be independent from state boundaries, and which would not allow for distinctions based on the nationality of involved persons or on the territoriality of situations.
In the book, Ratner undertakes three operations: First, he identifies and fleshes out the thin-justice-standard. Importantly, “thin” does not mean “procedural” only, but has some substance. The standard consists of two principles or “pillars”, as Ratner calls them. The first pillar is the advancement of international and intra-state peace, the second pillar is the respect for basic human rights. In addition to a norm’s capacity to further peace and/or human rights, Ratner (at some places) employs two additional criteria: procedural fairness, as an expression of internal morality vis-à-vis participants and as an outgrowth of the rule of law (p. 409), and/or the prospects of such a norm for compliance.