ORIN KERR has more thoughts on the NSA interception program: “Based on what I have read from Risen’s book, it seems less likely to me than it did before that this is a TIA-like data-mining program. . . . For those with criminal law experience, this was basically a large-scale pen regsister/trap-and-trace or wiretap, depending on how the filters are configured. (I’m not sure how different telephone traffic is these days, at least inside the provider switches.) This is different from a data-mining program.”

If it’s a pen-register type program, of course, no warrant is required, as it’s pretty well established that there’s no expectation of privacy in “envelope” type information, even if it’s normally read only by machines, not human beings. Orin also has some thoughts on why the disclosure of this information might be damaging to national security.