> What do you make of Snowden's assertion that he could have eavesdropped on anyone he wanted? Was he failing to mention that his actions could be audited? Was he failing to mention that he had access to someone else's PKI with which to do the surveillance? Other?
I think he was not really telling the truth. And I don't mean that he intended to be dishonest, but rather, he was trying to explain the issue as he understood it in a simplified manner. My understanding is that he did not actually have access to XKEYSCORE and other tools, so he did not known how they actually worked and the associated red tape. He could only go by what the presentation slides that he downloaded from NSA had said (I am assuming that those slides did not describe much regarding the associated red tape because it was meant for those who had already been read in and had access to the program so they would have already been fully aware of the legal and compliance side of things, along with continuous training and review of the Constitution). Snowden had to get the materials regarding programs he didn't have access to by authenticating with the smartcard/PKI of colleagues who did have access to those systems (Source: http://msnbcmedia.msn.com/i/msnbc/sections/news/NSA_Snowden_...).
> Which agency is the process you described applicable to?
NSA. I don't think there would be another agency with access to this alleged wiretap.
> Are you certain it is the same in other agencies?
I am not certain. I do believe it is the case though, as my understanding is that DoD and IC IG have this authority not specifically NSA (If you are aware of an agency not properly protecting USPI as they should be, the IC IG would definitely want to hear about it, I am very serious).
> Are you aware of any loopholes (or might Snowden have been?) which would have allowed it to happen without consent from higher level officials?
I am not aware of any, so definitely cannot conclude that they do not exist. There could possibly be a case to be made there, as the "data" versus "metadata" debate awhile back demonstrated that some things are interpreted in a way that could allow for overreach. I personally don't think it is productive to assume that loopholes were utilized until there is evidence of that. Additionally, any loophole would be for accessing the information but the way the system is setup at least these days would not allow for that to occur without an audit trail ("tag the people, tag the data!").
> the FISA warrant argument
If I understand correctly, the following still could have happened and I don't know if anyone has disputed it:
1. Trump associate spoke to someone who was subject to FISA collection or regular collection of a foreign target of interest.
2. Topic was discussed which specifically related to the US Person (Trump associate) which was serious enough to warrant de-minimization of the USPI.
3. The proper process was followed, and the evidence was solid enough to de-minimize the US Person's side of the conversation.
This interestingly would mean that (1) it was serious enough to warrant de-minimization but not enough to be conclusive proof of malice, which is something that anti-Trump folks would not want to hear, and (2) it was a discussion of interest involving an intelligence collection target, which is something that pro-Trup folks would not want to hear. Therefore this potential exact scenario is not within the interest of either side and I have not heard it discussed much.
There are many possibilities, some which are politically convenient to either side, others which are not convenient to either side. It might be mildly amusing to discuss but as far as I understand, an actual investigation into this is going to occur and either we will get answers to all of this based on a comprehensive audit of those who accessed the intercepts and/or was responsible for the tasking.