"First, I don't agree that they rubber-stamp warrants, but believe they evaluate them on a case-by-case basis"
The FISC is called a rubber stamp because they almost never reject requests for a warrant. The government can be almost certain that no matter how outrageous its request is, FISC will say "yes." That they may be evaluating requests on a case-by-case basis is irrelevant if they always come to the same conclusion.
> The FISC is called a rubber stamp because they almost never reject requests for a warrant.
Given that they initially provide feedback when they have problems rather than outright rejection, and that the government can, if it isn't willing or able to address the feedback, simply withdraw the application, its not entirely surprising that they don't issue rejections, per se, nor does that necessarily indicate that they are acting as a rubber stamp.
We'd probably get a better picture of whether they were a rubber stamp if they were required to give a rejection with comments if the application wasn't sufficient on its face, and we had statistics on that.
The FISC is called a rubber stamp because they almost never reject requests for a warrant. The government can be almost certain that no matter how outrageous its request is, FISC will say "yes." That they may be evaluating requests on a case-by-case basis is irrelevant if they always come to the same conclusion.