Since my piece yesterday, my little grey cells (such as they are) have been beavering away.
The following is, I believe, the thinking informing the rather strange antics of the Video Doctor (as described in yesterday's piece):
Once the text of a torture/detainee bill had been settled between the WH and Congressional GOP leaders, the imperative was to get it enacted this week.
Naturally, the issues involved - especially the habeas corpus provisions - would entail the passage of a cloture motion. And, given the time pressures and the ability of a handful of senators to run down the clock (at least over two or three days), cloture was far from a cinch.
So Frist set up a choice for the Dems: he took the Mexican fence bill (HR 6061), the other legislative target for this week, and proposed an amendment containing the agreed text of the detainee bill.
He then locked off further amendments to the fence bill by filling the amendment tree.
(I'm fairly sure how this works now - in principle: under Senate rules, there are a limited number of amendments which can be the pending business (this CRS Report explains further). The Majority Leader, exploiting his right to be called over all other senators, offers a series of insubstantial amendments such that no other senator can offer any further amendment.
In conjunction with a cloture motion, this gives the majority leadership something of an equivalent to the previous question in the House.)
Filling the amendment tree is a hostile act, inviting retaliation from the minority, who, naturally wish their own amendments to be debated and voted on.
In particular, some minority senators who might have been prepared to vote for cloture could chose to oppose it on the grounds that their rights had been abused.
That's where the choice came in: Frist offered the Dems a unanimous consent agreement whereby they would be given floor time and a vote on four or five of their amendments in exchange for agreeing to proceed straight thereafter to the vote on passage.
What was in it for the Dems? Not just a chance to bloviate, but, with the Specter amendment on habeas corpus, a chance to change the bill in a way unacceptable to the GOP. Putting them in a spot of either pulling the bill or trying to get round the amendment via a signing statement. Either way, the Dems would have rained heavily on one of the GOP's rare parades these days.
What was in it for Frist? The timing of cloture motions is tricky - especially if you need two of them, one on the motion to proceed and one on the vote on passage. Avoiding cloture would have helped his scheduling of business in a week with a hard deadline.
Plus - if he was unsure of some of his Dem cloture yeas, he'd want to woo them with the senatoriality of a compromise for extra debating time and votes so that they didn't oppose cloture out of pure orneriness (as he would see it!).
On the other hand, by rolling the detainee bill into the fence bill, he'd make it all the more tricky for Dem moderates to oppose cloture. That would make the threat of this scorched earth alternative more realistic.
As we know, the Dems accepted the UCA offer - and came tantalizingly close on the Specter amendment.
The result of the vote on passage of S 3930 (not to mention Uncle Harry's expressed openness to compromise) suggests that, had the Dems decided to hang tough and rest everything on a whip count pissing contest on cloture of HR 6061, they would more likely than not have lost - and thereby lost the chance of putting pressure on the GOP via the habeas issue.
That's the way I see it, at least.