We were addicted to Nate Silver's 538 blog during the 2008 campaign, but had been so buried in tracking umpteen health blogs that we hadn't checked back too often lately.

Paul Krugman showed us the error of our ways. Silver has one post—who gets money and opposes public plan—that is getting a lot of attention in the blogosphere. We also scrolled back and found a few other great insights about the AMA and other health reform factors... (About Iran too, but we digress.)

Silver isn't so unsophisticated as to suggest that there is a straightforward correlation between getting a campaign contribution and opposing the public plan. This particular analysis, in fact, doesn't look at whether the lawmaker in question is also getting contributions from groups that back the public insurance plan. Nor does it identify exactly what it means by "public plan," atlhough since the list of "yes" "no" and "maybe" votes comes from a Howard Dean, in this context it's probably a Medicare-like public plan.

A lot of the more centrist to conservative Democrats, like Nebraska's  Ben Nelson, Indiana's Evan Bayh, Arkansas' Blanche Lincoln are, in fact, moderate to conservative Democrats from moderate to conservative states and it's no surprise they are on the fence about a public plan (They may be more open to some of the alternatives being discussed. Or at the end of the day—or at the end of next October—be willing to live with some version of a public plan if they conclude there is enough other good stuff in the final bill). Opposition to, or at the very least skepticism about, a public plan is pretty consistent with their voting record and ideology.

Silver finds, however, that a number of what he calls "mainline Democrats" seem more likely to be swayed by lobbying. He writes:

The insurance industry's influence appears to swing about 9 votes against the public option. Whatever number of senators wind up supporting the public option, add 9 to it, and you'll have a decent ballpark estimate for what the level of support might be if not for insurance industry contributions. Note, however, that we haven't attempted to model the impact of contributions from other interest groups, including both pro-health reform organizations such as labor unions or other stakeholders like pharmaceutical companies.

So I've bookmarked 538 again, to learn more about the magic number nine.