Actually, it appears they can rest secure in the confidence that they don't actually HAVE to do anything, and at least some paranoid people will give them credit for whatever happens anyway :~D
I see. So, in other words, accepting the words of the DHS at face value when they warn us that things like, for example, bridges, are prime terrorist targets -- and then observing that they persuade police across the country to dispatch when someone is observed photographing a bridge -- or even observing a bridge -- is evidence of mental pathology.
And your qualifications as a DSM-flogger are exactly what, "doctor"?
Would I be out of line suggesting that if you... ahem, "they" don't want people to think "terrorism" when a bridge kabooms, they shouldn't keep warning us to be on the lookout for terrorists trying to make bridges go kaboom?
Oh, sheesh, why am I asking you? You've obviously got either delusions of grandeur, a "post-for-hire" gig, or, a seriously warped sense of troll-humor. Sorry I wasted your^H^H^H^H^H my time.