Rawls first introduces the idea that persons are self-originating sources of valid claims in his 1980 Dewey Lectures as a central element of what he there calls “Kantian Constructivism.” Although this got lost in Rawls’s political turn in Political Liberalism, I argue that the claim that persons are self-originating sources of claims – or, in my terms, that they share a basic second-personal authority to make claims and hold one another accountable – can do real work in grounding justice as fairness (and also “rightness as fairness”) that the Kantian Interpretation in A Theory of Justice is impotent to do. Taken on their own, the materials of the Kantian Interpretation are impotent to support anything in the distinctive conceptual territory of the right, much less, the priority of right. Only the idea that we are fundamentally accountable to one another puts us into the conceptual space of the deontic.