Tonight’s vote in the Senate is going to get a lot of media attention and a victory will be considered a big win of proponents of proposed health care reform.  It will be, to be sure, since a loss on this vote would be devastating for them.  But, as Jay Cost describes here, this a vote about process and many Senators who aren’t committed to vote for the legislation may vote tonight to let the debate begin. Jay highlights three reasons that wavering Senators will likely vote aye:

(a) “Keep the Ball Rolling”. Tomorrow’s vote – like all of the votes to date – is a process vote, meaning that Obama and the leadership can argue, “Vote yea to keep the process going. We can improve the bill later if you stick with us.”…

(b) No Harm For Yea. GOP candidates could conceivably tie tomorrow’s vote to a vote for health care, but that’s a very specious argument to make. I would guess that local newspapers and television outlets would call them out on it. Plus, if (for instance) Blanche Lincoln votes yea tomorrow but ultimately votes against closing debate – those ads would be very ineffective. What’s more, there is an easy rejoinder, which we are already hearing: “I voted to open debate. What’s so bad about debate?”

(c) Lots of Harm for Nay. A nay vote would gravely damage prospects for reform. And legislators on the Democratic side do not want to kill reform unless/until they absolutely have to, i.e. voting in favor on a particular item would seriously hurt their political careers. As noted above, a yea vote tomorrow will not damage anybody’s political prospects. A nay vote, on the other hand, would make that senator a pariah in the broader party (the interest groups, activists, and enthusiasts on the Democratic side) – which, I hasten to add, is the primary funding source for all of these members. Lieberman’s Independent Democrat status makes him basically half a Dem and half a GOPer. He’s voting yea, which should tell you all you need to know.

In other words, no matter what happens tonight, there is still a big battle ahead.