Brad Plumer deplores the low emphasis on white collar crime at the FBI these days, and wonders if more severe prosecution of white collar crime might be even more effective than prosecution of other crimes since the Ken Lays of the world are presumably rational actors, susceptible to incentives, while it is less plausible that this is the case for the typical murderer.
I think that this probably even applies beyond cases like murder where rationality is unlikely to be involved, and into crime motivated by rational or semi-rational economic considerations. For those in poor, socially marginalized groups, harassment by officialdom is a regular and expected part of life. Thus, it is not surprising that the fear of such harassment is not as effective as we would like in modifying their behavior; keeping their noses clean is by no means guaranteed to protect them from harassment. Furthermore, their circumstances being what they are, the potential benefits of criminal activity may be particularly desperately needed goods.
Conversely, it is extremely uncommon for one of higher status to face official persecution for no reason at all. Even when innocent upper-class types are targets of government harassment, this is usually a product of the actions of an identifiable rival, and not a general background condition which is unavoidable and expected. Further, it is usually a lot easier for one of higher social class to get by reasonably well without engaging in crime. Since the benefits of crime are usually less for the white collar criminal (diminishing marginal utility of money, etc.) and the contrast between being prosecuted for criminal activity and the normal state of affairs is greater, it seems that such prosecution and punishment should be a more powerful motivator for a rational white collar criminal than for a rational petty criminal. Of course, as things actually stand, white collar criminals are hardly ever caught; given these considerations, one must imagine that the reasonable expectation of such criminals that they will avoid punishment contributes greatly to their indifference to such punishment, and so to the disturbing frequency of white collar crime.