However, I think that a brief excerpt from his posts on Mukasey's tearful insinuation that FISA caused 9/11 might be useful to people too rushed to read the whole thing.
Attorney General Michael Mukasey ... claimed that, prior to 9/11, the Bush administration was aware of a telephone call being made by an Al Qaeda Terrorist from what he called a "safe house in Afghanistan" into the U.S., but failed to eavesdrop on that call. [snip]
In that speech, Mukasey blamed FISA's warrant requirement for the failure to eavesdrop on that call
People who should know about such a call have no idea what Mukasey was talking about.
Greenwald points out that no warrant, not even a FISA warrant, would be required to listen in to such a call.
Now the Justice Department explains to Greenwald that "This call is also referenced in the unclassified report of the congressional intelligence committees' Joint Inquiry into the 9/11 attacks."
Greenwald infers that they must be referring to a call from the USA to the safe house (the DOJ e-mail does not make this detail clear so they do not admit that Mukasey misspoke).
This also hints at how FISA might have been relevant. To intercept all calls to and from the phone in the USA used to call the safe house, the NSA would need a FISA warrant or a temporary emergency waiver. However, if Greenwald is correct about which call is in question, they could not have been restrained by FISA from intercepting because they did not know that the phone was in the USA. He quotes from the the unclassified report of the congressional intelligence committees' Joint Inquiry into the 9/11 attacks.
"The Intelligence Community did not identify the domestic origin of those communications,"
thus they could not have been restrained either by FISA, or by excessive respect for the spirit of FISA, since they didn't know that FISA had any relevance to the call in question or the phone from which it was made.
To tap the phone from which the call was made, the NSA would have needed a FISA warrant or an emergency waiver. However, since they didn't know this, FISA could not have prevented them from doing anything they would otherwise have done.