Plato describes the constitution of the Republic as faithful to the saying according to which « among friends, everything is common » and he also calls friends the citizens of the Laws. The present pa-per suggests that the nature of the communi-ty implied in the idea of political friendship in Plato is mani-fold and that it should be understood in the light of the two forms of the common known in Archaic and Classical greek thought: the exclusive common, i.e. a common ressource to be set apart from individual possessions, and the inclusive common, i.e. a community ba-sed on the equality of individual possessions. The constitutions of the Republic and of the Laws can thus be seen as two types of communism, adapted to two different kinds of situation and citizen, depending on whether individual property and fami-lies are allowed or not. The first kind, the communism of the Republic, inspired by Aristophanes, makes all individual prop-erty collective: goods are used in common because they are not individually assigned; in the second kind of communism, the one exposed in the Laws, all individual families have equal shares of a good, which is there-fore perceived as common. This is how Plato conceives the two best form of government, but he does not determine whether there could be a third form of go-vernment where there would be enough community to establish political friendship.