I'm still convinced that Republicans are making a mistake in forcing a cloture vote on the motion to proceed.
Everyone is acting as if this is a necessary first step, but it isn't. Regular Senate procedure is actually to consider bills under unanimous consent agreements, which can set up rules for the entire consideration of the bill, or just get things started. Forcing a motion to proceed is only necessary if the minority won't agree to things such as which amendments will be considered, for how long, and in which order. A partial UC agreement is the normal solution to a situation in which the minority intends to eventually filibuster. The key is that the minority loses nothing by allowing the bill to reach the floor -- except for the chance to kill it before that point.
And, as I argued before, voting against cloture on the motion to proceed is a far tougher sell to marginal Democrats than cloture on the final bill. Right now, Ben Nelson and friends would have to argue that the bill is so bad that it shouldn't even be considered -- or, they would have to argue that allowing the bill to come to the floor is the same as voting to pass it. Of course, pols can make whatever arguments they want, no matter how illogical or implausible, but I can't imagine that marginal Democrats, trying to show that they are non-ideological and reasonable, would be comfortable with either of those arguments. After all, Nelson, Lincoln, and the others say that they're for health care reform, just not liberal versions of health care reform. That's hard to square with blocking all debate on the bill.
A much better set of arguments will be available to marginal Dems who want to oppose (final) cloture on the bill, down the road. At that point, they don't have to say that they're trying to kill the bill; they can just say that they don't want to rush anything, and that all amendments should be considered carefully (there are always more amendments!). Or, they can at that point say that the bill is turning out to be just too liberal, if that's how they want to position themselves.
Republicans, however, are warning that such vote patterns will be attacked as flip-flops. Now, it makes sense for Republicans to attack those who vote for final cloture but against the bill; that's a combination that passes the bill. But it makes a lot less sense, if their goal is to kill the bill, to signal that cloture on the motion to proceed will be treated as a vote or against the bill. By doing so, they are fighting on their weakest, not their strongest group. The problem for Republicans is that if marginal Dems will wind up supporting moving the bill to the floor -- and if those Dems know that they will consequently be attacked as if they voted for final passage, whatever else they do -- then the incentives for voting against final cloture disappear. At that point, having earned the maximum opposition from Republicans, marginal Dems will have all the electoral incentives pointing to voting yes on final cloture.
Let me put it another way. The fight over marginal Democrats in the Senate has, from the beginning, been all about the incentives those Democrats have to appear to be reasonable centrists. The more that Republicans show that they are against any type of health care reform, the more that center recedes, and marginal Dems are left with little incentive to oppose mainstream Democrats. Forcing a vote on the motion to proceed (and stunts such as forcing a full reading of the bill) only show that Republicans are uninterested in compromise; their only goal is to defeat and delay the bill. It may be a good way to get marginal Dems to cast votes that can be portrayed as liberal, but it's a lousy way to stop the bill.