“Corruption is ... a status. A person, when corrupt, has changed. Evil has captured her being, her essence, her soul. It is a searing indictment, somehow not only of A’s act but of A’s character. It is a statement not only of what A has done, but of what A has become.”
That is a quote from a new paper by Lawrence Lessig ("Institutional Corruption," March, 2013). That distinction, between good and evil, is at the core of what corruption is, which we have not studied much . . .
Another view of corruption is evolutionary, and it is in contrast with the quote above: corruption in some societies might be the default status, and it disappears when Good captures the person, and that probably happens with time.
Hopefully norms and then rules evolve un such a way that Good become more prevalent.