I think Mark's take on it is exactly right,
I'm not privy to any insider anything, but I'm pretty sure that either they don't have the votes, or they're not sure they have the votes. Either way, they're stuck. For now, it's all bluster while they figure out what to do.Everything I have read says that Frist doesn't have the votes. Even Republican's say he doesn't have the votes. This may be an attempt by Frist to try and shore up his position. If he blows this, he's can kiss any further advancement in the Republican Party goodbye.
Just this past Sunday, Pat Robertson panned any chance of Frist's Presidential aspirations. Frist's participation in the Family Research Council's "Justice Sunday" circus was designed to garner support in the religious conservative community. His future hangs on his handling of the nuclear option.