With all the talk about the failure of airport security to detect the PETN that the Christmas bomber sewed into his underwear -- and to think I've been using the phrase "underwear bomber" as a joke all these years -- people forget that airport security played an important role in foiling the plot.
In order to get through airport security, Abdulmutallab -- or, more precisely, whoever built the bomb -- had to construct a far less reliable bomb than he would have otherwise; he had to resort to a much more ineffective detonation mechanism. And, as we've learned, detonating PETN is actually very hard.
Additionally, I don't think it's fair to criticize airport security for not catching the PETN. The security systems at airports aren't designed to catch someone strapping a plastic explosive to his body. Even more strongly: no security system, at any airport, in any country on the planet, is designed to catch someone doing this. This isn't a surprise. It isn't even a new idea. It wasn't even a new idea when I said this to then TSA head Kip Hawley in 2007: "I don't want to even think about how much C4 I can strap to my legs and walk through your magnetometers." You can try to argue that the TSA, and other airport security organizations around the world, should have been redesigned years ago to catch this, but anyone who is surprised by this attack simply hasn't been paying attention.
EDITED TO ADD (1/4): I don't know what to make of this:
Ben Wallace, who used to work at defence firm QinetiQ, one of the companies making the technology, warned it was not a "big silver bullet".[...]
Mr Wallace said the scanners would probably not have detected the failed Detroit plane plot of Christmas Day.
He said the same of the 2006 airliner liquid bomb plot and of explosives used in the 2005 bombings of three Tube trains and a bus in London.
[...]
He said the "passive millimetre wave scanners" - which QinetiQ helped develop - probably would not have detected key plots affecting passengers in the UK in recent years.
[...]
He said the "passive millimetre wave scanners" - which QinetiQ helped develop - probably would not have detected key plots affecting passengers in the UK in recent years.
[...]
Mr Wallace told BBC Radio 4's Today programme: "The advantage of the millimetre waves are that they can be used at longer range, they can be quicker and they are harmless to travellers.
"But there is a big but, and the but was in all the testing that we undertook, it was unlikely that it would have picked up the current explosive devices being used by al-Qaeda."
He added: "It probably wouldn't have picked up the very large plot with the liquids in 2006 at Heathrow or indeed the... bombs that were used on the Tube because it wasn't very good and it wasn't that easy to detect liquids and plastics unless they were very solid plastics.
"This is not necessarily the big silver bullet that is somehow being portrayed by Downing Street."
A spokeswoman for QinetiQ said "no single technology can address every eventuality or security risk".
"QinetiQ's passive millimetre wave system, SPO, is a... people-screening system which can identify potential security threats concealed on the human body. It is not a checkpoint security system.
"SPO can effectively shortlist people who may need further investigation, either via other technology such as x-rays, or human intervention such as a pat-down search."
