And that, not racism, is the biggest part of the problem.
Once they've pegged you, you're ready to go to jail unless you've got lots of money to defend yourself.
One of the problems is that certain minorities are just more likely to be pegged than others. THe way our current justice department works, a white middle class kid getting caught with pot will be given a slap on the wrist for a first time offense, but it is much more likely that a black kid of the same age would get prosecuted to the fullest extent of the law for a first time non-violent offense.