I have not read all this thread, so I don't know if this has been posted. The writer is not exactly a friend of big government by either party.
http://www.volokh.com/2013/06/06/the-fisa-court-order-flap-take-a-deep-breath/
[T]his is not some warrantless or extra-statutory surveillance program. The government had to persuade up to a dozen life-tenured members of the federal judiciary that the order is lawful. You may not like the legal interpretation that produced this order, but you can’t say it’s lawless.
In fact, it’s a near certainty that the underlying program has been carefully examined by all three branches of government and by both parties. As the Guardian story makes clear, Senator Ron Wyden has been agitating for years about what he called an interpretation of national security law that seems goes beyond anything the American people understood or would support. He could easily have been talking about orders like this. So it’s highly likely that the law behind this order was carefully vetted by both intelligence committees, Democrat-led in the Senate and Republican-led in the House. (Indeed, today the leaders of both committees gave interviews defending the order.) And in the executive branch, any legal interpretations adopted by the Bush administration would have been carefully scrubbed by President Obama’s Justice Department. ...
Imagine that the United States is intercepting al Qaeda communications in Yemen. Its leader there calls his weapons expert and says, “Our agent in the U.S. needs technical assistance constructing a weapon for an imminent operation. I’ve told him to use a throw-away cell phone to call you tomorrow at 11 a.m. on your throw-away phone. When you answer, he’ll give you the number of a second phone. You will buy a phone in the bazaar, and call him back on the second number at 2 p.m.”
Now, this is pretty good improvised tradecraft, and it would leave the government with no idea where or who the U.S.-based operative is or what phone numbers to monitor. It doesn’t have probable cause to investigate any particular American. But it surely does have probable cause to investigate any American who makes a call to Yemen at 11 a.m., Sanaa time, hangs up after a few seconds, and then gets a call from a different Yemeni number three hours later. Finding that person, however, isn’t easy, because the government can only identify the suspect by his calling patterns, not by his name.
So how does the NSA go about finding the one person in the United States whose calling pattern matches the terrorists’ plan? Well, it could ask every carrier to develop the capability to store all of their calls and to search them for patterns like this. But that would be very expensive, and its effectiveness is really only as good as the weakest, least cooperative carrier. And even then it wouldn’t work without massive, real-time information sharing — any reasonably intelligent U.S.-based terrorist would just buy his first throwaway phone from one carrier and his second phone from a different carrier.
The only way to make the system work, and the only way to identify and monitor the one American who is plotting with al Qaeda’s operatives in Yemen, is to pool all the carriers’ data on U.S. calls to and from Yemen and to search it all together — and for the costs to be borne by all of us, not by the carriers.
In short, the government has to do it.