What I've not seen mentioned at all in this scandal

All debate of the rightness of Snowden's disclosure aside, there's one key piece of information I've not seen mentioned anywhere.  The President, the Speaker of the House, and many members of the Senate have come out saying that this program was legal, it was approved by congress, vetted by the courts, and the idea that this is somehow illegitimate has absolutely no basis.  But I think it does.  You see, the one missing element in all of this is that this sweep of meta-data is being handled by the NSA.

So what?  The NSA is certainly well equipped to handle this volume of data.  Communications Intelligence is their mission after all.  But there's one sticking point, and it's a doozy:

"The COMINT mission of the National Security Agency (NSA) shall be to provide an effective, unified organization and control of the communications intelligence activities of the United States conducted against foreign governments, to provide for integrated operational policies and procedures pertaining thereto. As used in this directive, the terms "communications intelligence" or "COMINT" shall be construed to mean all procedures and methods used in the interception of communications other than foreign press and propaganda broadcasts and the obtaining of information from such communications by other than intended recipients, but shall exclude censorship and the production and dissemination of finished intelligence."

The NSA may not, by its own charter, perform Communications Intelligence operations upon the United States or its citizens.  It's target, and mission, is COMINT ops on foreign targets.  Now, I am certain the Administration will claim that the actual targets of this program are foreign terrorists.  However, the one overriding law that the NSA must follow is the United States Signals Intelligence Directive (or USSID) 18.  I would draw your attention specifically to the unredacted portions of Sections 4 and 5, which specifically deal with how communications collected from sources known to be US citizens are to be handled.  I won't quote directly (you can read it all there) but in short, they can't.  They are forbidden by federal law from collecting, processing and disseminating Signals Intelligence gathered from US Citizens.  And I don't really care how the Administration spins it, this meta-data collection and processing, especially as laid out in everything we've seen, is in direct contravention of USSID 18.  And that makes it a federal crime.