PRISM

[Lamplighter]

The hypothetical example in PH45's link is far too tenuous to carry much weight at all.
It basically tries to argue that the phone companies can not manage the author's imaginary problem,
therefore only the government is capable, and therefore must do it.

"must" ? Why "must" ?

Even the author's final paragraph pre-supposes the "must"

But for those who don't like the alternative model, the real question is "compared to what"?
Those who want to push the government back into the standard law enforcement approach
of identifying terrorists only by name and not by conduct will have to explain
how it will allow us to catch terrorists who use halfway decent tradecraft
-- or why sticking with that model is so fundamentally important that
we should do so even if it means more acts of terrorism at home.

My hypothetical would be to change only the timing in his example.
Instead of urgency, the terrorists use the postal services of each country.
So now, would that justify a government database of the addresses
and return addresses on every piece of mail handled by the post office ?
Who knows, maybe such already exists.

Although some aspects of physics posits an infinite number of parallel universes,
we don't build our lives around that possibility.
The Boston Marathon bombing shows that a program that has been
in operation for at least 7 years failed to do what it is supposed to do.

Sometimes, absolute safety is not possible for all the possible hypothetical or imaginary situations.