Just Person and Just Polis

Plato's concept of the relation between a Just Person and a Just Polis as a Writ Small-Writ Large analogy, entails that the two conditions are mutually independent.  It therefore further entails the possibility of a Just Person inhabiting an Unjust Polis.  However, the concept of Justice as an internal condition avoids the complication that a Person has external relations within a Polis, to which that concept seems inadequate.  Thus, for example, that someone does an honest day's work on an assembly line in the manufacture of gas chambers in Germany in 1942 seems, at minimum, to complicate Plato's concept of a Just Person.  Perhaps a better indication of the inadequacy is an example of what might be required to eliminate the complication.  Whether or not Plato would subscribe to it, Leibniz offers such an elimination via his two theses--external relations between Monads are illusory, as is any apparent disharmony between them.  Absent such difficult to confirm theses, Plato's concept of Justice is problematic.