Asset forfeiture was conceived as a way to cut into the profit motive that fueled rampant drug trafficking by cartels and other criminal enterprises, in order to fight the social evils of drug dealing and abuse. Over time, however, the tactic has turned into an evil itself, with the corruption it engendered among government and law enforcement coming to clearly outweigh any benefits.
Read article here...but this paragraph sums it up simply...
Law enforcement agents and prosecutors began using seized cash and property to fund their operations, supplanting general tax revenue, and this led to the most extreme abuses: law enforcement efforts based upon what cash and property they could seize to fund themselves, rather than on an even-handed effort to enforce the law.
http://wapo.st/1wO9OPD