I don't understand why SATTSO is having so much trouble explaining this, but I do understand the confusion here. As I understand it, the policy has changed significantly since Gilmore. It doesn't violate that case, but makes that case less relevant.

As I understand it, the policy in effect at that time was that there were two cases: you either showed "acceptable" (where the definition of the has changed slightly) ID or went through secondary screening. That policy has changed (and it had to or the NFL has no meaning).

The new policy, also as I understand it, mostly separates the issue of ID and secondary screening. Now, being able to identify oneself is a requirement to fly. That can be accomplished by showing the listed set of IDs or by showing other IDs, going through a verification process based on public records, or a combination of the latter two. If that's successful, then a secondary is not required, but may be needed in some cases. So I have the following questions for SATTSO:

(1) Is the above correct at the level of detail that I've presented it?
(2) Does the SOP state the mix of other ID vs. verification that's allowed or is that up to the discretion of the STSO?
(3) Is there a firm rule as to when a secondary is required?
(4) If #3 is "yes", is that SSI? If not, what is it?
(5) You implied that even if the verification wasn't successful, the passenger may still be allowed to fly. Can you clarify that?

What I found interesting here is that some of what's in this thread disagrees with what a checkpoint supervisor told me at TPA. After clearing, I asked him about what options I had while my passport was being renewed. I showed him a handful of other ID (most of which had pictures) and he said that wouldn't help. I asked about the ID verification and he said it was risky since "if you make a mistake, you won't fly". Most of that is at odds with what's been posted here and other threads. Perhaps you can comment on that issue too.