The System Worked. Kinda.

TSA watcher Bruce Schneier looks at the bright side:

[P]eople 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.