In the Republic Socrates gives three different accounts of the city
at war: though they have been little discussed, each plays a crucial
role in Socrates' praise of justice. In the first account, in book
II, the luxurious city engages in wars for expansion. In the second,
in book III, the best city, now seen as the perfectly unified city, fights
actual cities that are always riven by class conflict. In the third,
in book V, the best city uses war to educate its citizens, and to teach
other Greek cities not to enslave Greeks. Taken together these accounts
show the both the possibility of justice and the contingency of its circumstances.
In examining them we must confront our own judgements about the justice
of war, and our hopes for a world that would be spared of it.