Senator Snowe’s decision not to support the Baucus health-care-reform bill caught many observers by surprise. That leaves Baucus’s bill without a single GOP senator supporting it. Unfortunately, Senator Snowe’s statement on the matter doesn’t explain much. (I just returned from the Capitol where I was hoping to ask Snowe a few questions leaving the Senate Chamber, but she appears to have made herself scarce.) Anyway, perhaps Snowe will explain her decision in further detail, but it appears there are three broad reasons — in order of descending probability — for why Snowe isn’t on board with Baucus’s health-care-reform bill:

1) It’s simply a bad bill. If a Democratic senator is calling it a “big, big tax” it would seem that Snowe can hardly justify it as being fiscally responsible. The Baucus bill is just the worst of both worlds — it will cost a lot and it won’t do much.

2) It’s about leverage. Snowe has sort of become the Sandra Day O’Connor of the Senate. Getting anything passed depends on getting her to compromise. As we saw in the stimulus negotiations, Snowe can demand and get a lot of concessions from Democrats. Perhaps Snowe has been holding out to get something specific in the bill. Democrats don’t want to give it to her and now she’s calling their bluff.

3) It’s personal. Snowe might have some as yet unknown personal reason or conviction that prevents her from supporting the bill.

There’s also one other interesting aspect of the health-care-reform debate as it relates to Snowe. The national reform efforts seem to hinge on getting support from moderate Republicans — particularly Maine’s two senators. And yet, Maine passed it’s own health-care reforms in 2003 that contain many similar aspects of the national health-care reforms being proposed, such as requiring coverage of pre-existing conditions and a public-option mechanism. The result in Maine has been a fiscal and regulatory disaster. I wonder if this has influenced Snowe’s thinking about health-care reform.