Rich, maybe this will convince you:
http://www.schneier.com/blog/archives/2005/07/profiling.html
Ethics aside, institutionalized profiling fails because real attackers are so rare: Active failures will be much more common than passive failures. The great majority of people who fit the profile will be innocent. At the same time, some real attackers are going to deliberately try to sneak past the profile. During World War II, a Japanese American saboteur could try to evade imprisonment by pretending to be Chinese. Similarly, an Arab terrorist could dye his hair blond, practice an American accent, and so on.
Profiling can also blind you to threats outside the profile. If U.S. border guards stop and search everyone who’s young, Arab, and male, they’re not going to have the time to stop and search all sorts of other people, no matter how hinky they might be acting. On the other hand, if the attackers are of a single race or ethnicity, profiling is more likely to work (although the ethics are still questionable). It makes real security sense for El Al to spend more time investigating young Arab males than it does for them to investigate Israeli families. In Vietnam, American soldiers never knew which local civilians were really combatants; sometimes killing all of them was the security solution they chose.
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Whenever you design a security system with two ways through -- an easy way and a hard way -- you invite the attacker to take the easy way. Profile for young Arab males, and you'll get terrorists that are old non-Arab females. This paper looks at the security effectiveness of profiling versus random searching.
http://www.firstmonday.org/issues/issue7_10/chakrabarti/
If we are going to increase security against terrorism, the young Arab males living in our country are precisely the people we want on our side. Discriminating against them in the name of security is not going to make them more likely to help.