John Rawls based his theory of justice, in the work of that name, on a ‘Kantian interpretation’ of the status of human beings as ‘free and equal’ persons. In his subsequent, ‘political rather than metaphysical’ expositions of his theory, the conception of citizens of democracies as ‘free and equal’ persons retained its foundational role. But Rawls appealed only to Kant’s moral philosophy, never to Kant’s own political philosophy as expounded in his 1797 Doctrine of Right in the Metaphysics of Morals. I argue here that the structure of Kant’s political philosophy, with its categories of the innate right to freedom, private acquired right and public right, can clarify the relationship between Rawls’s two principles of justice and his scheme of basic liberties and primary goods.