Why?
I think that Graham and DeWine walked into this scheme to trick the rats knowing full well that they were going to take a hit from conservatives who were slow to figure it all out. And they did take a beating. (Curiously, there are still some people who apparently don't get it yet, even after Owens, Brown, Pryor and others have been confirmed, and even after it has been explained that Frist STILL has his finger hovering over "the button" and he can push it any time he wants. But NOW, thanks to the "extraordinary circumstances" language of "the deal", the rats are utterly boxed in and the nervous "blue state" GOP Senators have the cover they need to vote nuclear if and when the time comes. It still boggles my mind that the Democrats walked right into the trap. I can hardly stop smiling!)
The Republicans needed a couple of ringers in the "gang of seven" in order for the scheme to work. (The scheme was needed in the first place either because Frist was not certain that he had the fifty votes OR he figured that doing the "deal" was simply a superior strategy, especially from a PR point of view (with "the deal", the liberal press couldn't accuse the Republicans of "running roughshod", being "bullies", doing "incalculable damage to Constitution", "destroying Senate tradition", etc., etc. This is the kind of stuff the "blue state" Republican Senators were nervous about. But not anymore - - they got some COVER now! See, if the rats filibuster virtually ANYBODY, then the Republicans can throw up their hands and claim that the Democrats went back on their word. "We are left no choice, in the face of broken promises by the Democrats, but to change the filibuster rules at this time.")
I happen to believe that "the deal" was a masterpiece of political ingenuity that could only have been dreamed up by the ghost of Lee Atwater over breakfast with Karl Rove. And it could not have happened without the willing participation of Graham and DeWine. (It IS baffling that Graham is blabbing before the work is done, though. At least DeWine knows enough to stay cool.)