Corruption is how the privileged share their privilege (Latin for "private law") with the un-privileged. Sharing is good, right?
Corruption is as old as human history. For as long as people have organized themselves into groups with powerful leaders, those leaders have sometimes abused their power. But evolutionary biologists say corruption might actually be holding societies together.
Read more at io9.com
Their findings make a lot of intuitive sense - most people will continue to cooperate to keep their society together, in part because they don't want to be punished by law enforcers. People will tolerate a certain amount of corruption from their leaders and law enforcers as long as there isn't too much of it. Above a certain level of corruption, people stop seeing the point of cooperating and society begins to break down.