In an introduction to a French edition of Kant´s Zum ewigen Frieden, Charles Lemonnier, who was involved in the international peace movement, wonders why Kant had not touched the ´social question´ in this essay. In this paper, I take Lemonnier´s explanation of Kant´s silence concerning that issue, combined with his appreciation of the ironic format of the text as a starting point to analyse the irony in the essay. This analysis, in which, for heuristic purposes, Kant is compared (...) with Plato, demonstrates a connection of Kant´s irony with the rigour of his political philosophy, rooted as it is in the moral principle. The irony, thus conceived, is determined, pace Rorty, in many respects as genuinely Rortyan. This result is used to criticise a suggestion by Williams to abandon irony by going far enough in recognizing historical contingency as to no longer need it. (shrink)