Wouldn't the CIA and the FBI be sufficient to keep the gov abreast of hostile activity, foreign and domestic? They're big agencies with thousands of employees.
My point is, the gov doesn't need to be doing this. We have more security and local police have more firepower than Mohammedans seeking revenge and home-grown malcontents ever dreamed of.
So if they don't need to be doing it, why are they?
I'll answer my own question. I think partly this is just the geekiness of engineers -- a machine has the capacity to perform a certain function, and the guy wearing different-pattern plaids and a pocket protector, wiping his Cheeto™-stained fingers concludes it must perform that function.
And as some of us have known for almost 50 years, the US government IS a machine, and the machine is out of control.