I've been suggesting that what's in play here in this NSA matter is a new technology of some sort -- one which conducts searches in ways that you just can't get warrants for. And here Kevin Drum pulls together several threads of information that point in what figure is likely the correct direction.
He concludes by writing: "It seems clear that there's something involved here that goes far beyond ordinary wiretaps, regardless of the technology used. Perhaps some kind of massive data mining, which makes it impossible to get individual warrants? Stay tuned."
Like I said, a bunch of information I've heard over the last 48 hours tells me he's on the mark here. Not precisely, perhaps. I'm not sure it's data-mining precisely. Perhaps they're doing searches for certain patterns of words or numbers, perhaps something as simple as a phone number. But unlike 'traditional' wiretapping, in which you're catching the conversations of a relatively small and defined group of people, this may involve listening in on a big slice of the email or phone communications in the country looking for a particular phone number or code or perhaps a reference to a particular name.
From a technological point of view there's not really much outlandish about this at all. This is just the sort of thing the NSA is in the business of doing overseas. But you can see how this would just be a non-starter for getting a warrant. It is the definition of a fishing expedition.