Résumé : This chapter shows how the Stoic principles have been applied in Roman politics. It first goes back over the following assumption, generally taken for granted : the Agrarian reforms, started by the Gracchi brothers on the one hand, and the opposition of the roman conservative party on the other hand, would find their origin in two Stoic trends, initiated by, respectively, Diogenes of Babylonia and Antipater of Tarsus. The reality is in fact much more complex than that, and the Spartian organisation (and its heir, the City of Sun pictured by Blossius) obviously played here an important part. Secondly, it appears that the Stoic school produced more fighters for virtue than real politic opponents : for the Stoics, the question of the political organisation of the State is an indifferent one ; the only thing to be considered is to fight for moral principles, whenever they are threatened. The Stoics have therefore set up a series of opposition techniques (open conflict or passive disobedience, like silence and abstention), all ruled by the « retention clause », but also by clemency, benevolence, love of fellow countrymen, highlighted by Seneca and Marcus Aurelius.