This is all about maneuvering for votes. If Frist doesn't have the votes, it won't happen. If he does, it will.
But Frist has the authority as Leader to define this issue as a Litmus Test vote for every member of his caucus. By doing so he would have the backing of the President, the Vice President, the national party machinery and the "juice" advocacy organizations.
Torie, he is the best person to make it clear to each of the RINOs that they can fall in line, or face the destruction of their careers. It's hard to imagine even the most soft-headed among them -- Snowe, Collins, Chaffee -- failing to understand that they too will face another sort of Nuclear Option ... in primary season.
Sen. Frist needs to be spending more time as a Hard Ass, Top-Down Leader, and less time as a Touchy Feely Negotiator.