This article criticizes an empirical reading of On Perpetual Peace. It is also equally critical of the approach taken by philosophically minded scholars to give preference to Kant's philosophical outlook. Instead, it focuses on the peculiar oscillation between the philosophical and political aspects of the essay. Contrary to current concerns to update the conceptual framework of On Perpetual Peace—to rescue it from becoming obsolete—its salient irony, which mediates between both aspects, is singled out as a clue to an interpretation which seeks to account for both of them. Thus, the essay can still be a source of inspiration for peace research.