Well post festum, it looks like one of your explanations of the Senate's actions on the NSA spying case is more plausible:
Pat Roberts (R-Kansas), Saturday's NYT
"The irony of this is that it is portrayed now as administration pressure brought to bear on us, meaning the Republicans on the committee and basically me," Mr. Roberts said Friday. "It's just the reverse. It's the Republicans on the committee, my staff and myself, who have been really ? I don't want to say pressuring, but trying to come up with a reasonable compromise that will settle this issue. It was our activity that brought them along to this point, plus the possibility of an investigation."

I like how he mentions the "possibility of an investigation" at the end as the thing that makes the adminstration willing to talk about this at all.