Plato's Parmenides is regarded as a canonical work in ontology. Depicting a conversation between Parmenides of Elea and a young Socrates, the dialogue presents a rigorous examination of Socrates' theory of the forms, the most influential account of being in the philosophic tradition. In this commentary on the Parmenides, Alex Priou argues that the dialogue is, in actuality, a reflection on politics. Priou begins from the accepted view that the conversation consists of two discrete parts -- a critique of the forms, followed by Socrates' philosophical training -- but finds a unity to the dialogue yet to be discovered. By paying careful attention to what Parmenides calls the "greatest impasse" facing Socrates' ontology, Priou reveals a political context to the conversation. The need in society for order and good rule includes the need, at a more fundamental level, for an adequate and efficacious explanation of being. Recounting here how a young Socrates first learned of the primacy of political philosophy, which would become the hallmark of his life, Becoming Socrates: Political Philosophy in Plato's "Parmenides" shows that political philosophy, and not ontology, is "first philosophy." Alex Priou is lecturer in philosophy and the humanities at Long Island University.