One problem with profiling is that it can lead to abuse. Screening criteria can have a veneer of scientific objectivity, but still have the purpose and/or effect of singling out disfavored minorities. This is the same reason the Supreme Court came up with rules governing when, how, and where the police can set up sobriety check points. Without those rules, there is nothing to prevent the police from setting up their check points on the road leading to the neighborhood where all the black people live, for example. Maybe profiling is effective, I don't know, but can it be used in a way that guards against such abuse?