I don't know what the the hell Ptacek and crew are on about. Of course
defense-in-depth defense-in-breadth is effective. It's heresy to suggest otherwise. Myopic, short-sighted, and heretical, I say!
In support, I submit into evidence People's Exhibit #1, from here your honor:
...and I quoteth:
We use layers of security to ensure the security of the traveling public and the Nation's transportation system.
Each one of these layers alone is capable of stopping a terrorist attack. In combination their security value is multiplied, creating a much stronger, formidable system. A terrorist who has to overcome multiple security layers in order to carry out an attack is more likely to be pre-empted, deterred, or to fail during the attempt.
Yeah! Get some! It's just like firewalls, IPS, and AV, bitches! Mo' is betta!
It's patently clear that Ptacek simply doesn't layer enough, is all. See, Rothman, you don't need to give up!
"Twenty is the number and the number shall be twenty!"
How's that for a metric?
That is all.