A rights-based morality, if not universal, is not valid; it is merely the codified privileges of a victorious tribe, enforced in their own interest by the powers that made them victorious in the first place.
The moral character of such a regime is limited to relations among its citizens, while it is amoral (amoral at best, more typically, ruthlessly immoral) in it relations to those outside its own community; this typically means conquest, enslavement, subjection, or second-class citizenship (whether in law or in practice).
Put differently, constitutionality and the rule of law apply, strictly speaking, only to domestic matters involving citizens, not to matters involving foreigners or resident populations excluded from full citizenship.
Actions can only be moral — can only escape the self-serving partisanship of the survival machine (all animals prey on other living organisms, and even plants colonize territory and compete for resources) — in reference to those who account one another as fully empowered moral agents. In short, morality is nothing but mutual recognition between moral agents.
Thus, a valid social contract may hold among a group of citizens, and we may speak of justice among them and in reference to their relations with one another, while that group as a whole exercises an absolute tyranny over some excluded group.
This describes, to one degree or another, all ruling classes throughout human history, the American republic being a case in point.
Although a bold experiment in republican equality, the equality announced by Thomas Jefferson in The Declaration of Independence, extended fully only to white, male property-holders. Women and poor whites had some legal rights, although many of those were effective only by the agency of full citizens willing to act on their behalf (making of them dependents, analogous to children), while slaves had no meaningful rights at all.
While the American founding was not exemplary of full justice, a failing common to all foundings.
The coherence of any form of rights-based morality, whether the social contract or Kant’s categorical imperative, depends upon claims of inherent rights advanced by rational beings which recognize themselves as members of a community of rational beings, by appealing to the like right in all other members of that community. And this is as true for Hobbes as it is for Rawls.
Claims of rights that derive from the definition of rational and moral agency can be true if and only if they are true for all members of a virtual community so defined, and if and only if the methods of claiming and verifying such claims are accessible in principle to any rational being recognizing its membership in a virtual community of rational beings.
In short, universality of moral claims can only exist by means of the self-reflection of members of a virtual community capable of shared reasoning in a shared medium upon their shared membership in a community defined by its shared capacities for language and reasoning (for only by these capacities can moral agents recognize themselves in one another).
When All Is Said and Dunn 