Who are the 5 Dem crossovers? Not arguing with you, just wanna know. Also have you accounted for possible defectors like Chaffee, Snowe, Specter?
The RATS held the filibuster when we started with just 51 votes, because there would have been tremendous retaliation from Daschle if they had not stayed in line. But fundamentally, they did not want to filibuster -- they knew it ran against Senate tradition and similarly felt it was risky politics.
That list of Senators who will no longer filibuster includes Democratic moderates such as Lieberman, Nelson of Nebraska, Pryor of Arkansas, Lincoln of Arkansas, Johnson of South Dakota, Bingaman of New Mexico, Bayh of Indiana, Baucus of Montana.
Next, look at the freshmen RATS facing re-election in 2006. Do you think they want to suffer the same fate as Daschle, and being seen as obstructionists? Therefore, at minimum, you'll see Nelson of Florida, Carper of Delaware and perhaps others fall into line.
That gives us nearly a dozen RATS to pick off. As I said, getting to 60 from a base of 55 is a lot easier than getting there from 51.