In this week's Weekly Standard, Matthew Continetti laid out the usual case for the administration's position in the FISA debate. Julian Sanchez has a thorough, point-by-point rebuttal that's well worth your time. He highlights one new development of which I hadn't been aware:
We now have confirmation from the top national security lawyer at Justice that, as experts on FISA have been saying all along, foreign-to-foreign wire and radio conversations have never been and are not now subject to FISA. There is, rather, a limited problem with e-mails sent by a target that end up stored on a U.S. server, when we don’t know where the recipient is (or will be when he downloads the message).
This doesn't mean that there aren't some FISA warrant requirements that need to be tweaked, but it does mean that the situation is significantly less dire than many of the administration's defenders have suggested. That nightmare scenario of needing to get a warrant to listen to two people in Pakistan talk to each other is bogus.