That post continues to get a fair amount of traffic these many months later. Perhaps that's so because it's a masterpiece of reasoning and argument; perhaps it's because it's a pragmatic approach to subjects which are still topics of discussion and matters of concern for many of us; perhaps it's just because it was indexed by Google.
Today, Professor Tung Yin of the National Security Advisors blog discussed identification requirements and takes a similarly pragmatic position:
[E]ven if the ID requirement isn't perfect -- and no security system can be -- it does seem to serve a useful function. What are the downsides of requiring ID? [Privacy activist John] Gilmore, relying on an MIT paper, argued that it helps terrorists detect the weaknesses of the system by identifying who gets targeted for searches. Terrorists could, Gilmore argues, probe the system until finding some terrorist who manage to get through on "dry runs."
But I think there's a difference between an ID requirement as something that represents a threshold obstacle that must be passed, versus using ID checks as a basis for determining who to subject to secondary screening. Gilmore may be right about how terrorists can probe the system, but his complaint really seems to be about targeted searches, not ID requirements, unless the latter is used as part of the former.
Otherwise, I have a hard time seeing the downsides of requiring ID for travel on planes. I have to carry a driver's license to get to the airport anyway (unless I take a cab, which given the distance from home to the airport isn't really a good option in eastern Iowa), so it's no hassle to me to show it to the TSA agent at the head of the security checkpoint in the airport.
With both civil liberties and national security, the perfect is the enemy of the good.