My memory is fuzzy, but, back in the good old days, the only place I remember presenting an ID was at the ticket counter when getting a boarding pass and being subjected to the two stupid questions about your luggage. You didn't need and ID or even a boarding pass to go through security.

One could Monday-morning quarterback the 9/11 operation until the sun turns into a red giant about whether or not post-9/11 security procedures in place on 9/11 themselves would have thwarted the operation. Clearly, there were enough people and agencies asleep at the wheel for a couple of years, any one of which could have uncovered the plot. Everything beforehand -- the much-touted "layered approach" -- in one form or another failed, so the entire anti-hijacking and civil aviation security burden that day fell to airport screeners in Portland, Newark, and Dulles. In a similar fashion, the TSA will fail if all of the layers before them fail again. The biggest difference is that there is another layer of security beyond the TSA -- the passengers, flight crews, and hardened cockpit doors.

That being said, even OBL knew the 9/11 operation was operationally risky. In fact, some have documented that OBL himself reduced the operation from 20 planes worldwide to a handful on the east coast. Since he practiced strict compartmentalized security, we will never know explicitly who knew what among the 19-20 hijackers.

I've written before on FT why I believe a 9/11-style event won't happen again, and it has nothing to do with the TSA or a no-fly list. In a nutshell, here are my major reasons, written from the perspective of a retired military officer who participated in deliberate and crisis planning:

1. OBL quickly lost the element of surprise. Flight 93 knew what was going on and fought back. The Pentagon plane passengers knew what was going on but didn't have the time to fight back. I've never read (I haven't read extensively on the 9/11 incident, -- classified or unclassified -- so I could be wrong) whether or not the people on the second WTC aircraft knew what was going on. OBL knew that 20 planes was too complicated a mission, but something tells me that he expected to retain the element of surprise through all of the 4-aircraft operation.

2. They lost the element of surprise because they terribly underestimated the robustness of our communication systems. OBL sort of understood the need to use offensive information warfare, as demonstrated by training the hijackers to turn off the transponders. But, to retain the element of surprise throughout the entire operation, which really wasn't that long in duration, he needed to conduct a highly sophisticated information warfare attack, which only the most militarily competent nations in the world can pull off (on a good day).

3. The key vulnerability they exploited -- cooperation of the crew during a hijacking -- no longer exists. In fact, the vulnerability no longer existed by the time Flight 93 was hijacked. There are numerous stories about other commercial flights in the air on 9/11 and the makeshift measures aircrews implemented in real time to protect themselves, their cockpits, and their passengers.

Back on topic, showing IDs a dozen times to every TSA officer in uniform is irrelevant if nobody does anything before and afterwards. The various lists and random secondaries are irrelevant, but persist because they are visible and get people re-elected. The major flaw with no-fly and watch lists are that they are just that: lists and not real people. Think about all of the news stories before and after 9/11 pertaining to arrests of criminals at airports before and after they flew somewhere. This happened because real policemen did real police work long before the bad guy showed up at the airport. Heck, they even had a real arrest warrant they got approved by a real judge! Showing an ID to a ticket agent or TSA moat dragon was simply irrelevant in these police operations. As a matter of fact, frequent ID checks might have made the bad guy panic resulting in a blown arrest attempt.

So, "ID or not ID" really gets back to its roots -- preventing lost revenue. For the average citizen, it's a matter of privacy. Gilmore appears to have taken the privacy issue to task, but he didn't really challenge the "only terrorists fly with no ID" linkage between presenting IDs and mandatory SSSS.

But, as I have seen first-hand, the whole construct of post-9/11 civil aviation security is so terribly broken that, in the grand scheme of things, even a Gilmore victory would have been irrelevant. Because identity theft is so easy to do and more commonplace than most of us think, anybody in the homeland security apparatus who believes that ID checks add anything beyond trivial value to the security construct is clearly smoking something.