“Guerra giusta” e appello degli alleati in Tucidide

In the context of the late fifth century international relations, the unsteady balance among the poleis reveals the weakness of the agreements made earlier to ensure the international stability, as for the peace between Athens and Sparta in 446/5. In this perspective, the individual poleis resort to a series of arguments to defend and protect their position at the outbreak of a war. This paper aims to verify whether the use of the argument of the appeal by allies can be considered as a valid reason to justify an armed intervention. The two Athenian expeditions in Sicily (427-424 and 415-413) are exemplary for this purpose: in both of the situations Athens justifies its intervention with the request made by Leontini as for the first shipment and Segesta as for the second one, and this request is made in the name of blood ties and on the existence of a previous alliance, even if the sources highlight the speciousness of the argument. In the case of Plataea (427/6), the Thebans justify their involvement with the plea of a minority faction of Plataeans who wanted to defend their traditions. The policy of the appeal by allies is therefore to be taken into proper consideration for an assessment of the "just war" concept in the context of the late fifth century international relations.