Here is an eye-opening table revealing which Senators have received the largest contributions from PACs representing the insurance industry. Compare the names on the list to those who suggest it would be “unfair” if private insurers had to compete with a public-sector insurance plan that could offer better, less expensive insurance to all of us. The numbers come from this site. (Thanks to Brad F. for calling my attention to this website. )

Senator            Cycles     PAC $
Baucus (D-MT)       3.125      $141,250
McConnell (R-KY)   3.125     $110,750
Nelson (D-NE)       3.125      $106,123
Kyl (R-AZ)         3.125          $106,000
Gregg (R-NH)       3.125       $103,500
Grassley (R-IA)    3.125         $95,000
Lincoln (D-AR)     3.125         $91,000
Enzi (R-WY)        3.125         $87,000
Chambliss (R-GA)   3.125      $86,750
Ensign (R-NV)      3.125         $85,750
======================================
AVERAGE SENATOR          $37,267

On the website, Nate Silver explains that the table is “based on data downloaded from OpenSecrets.org, a.k.a. the Center for Responsive Politics. Contributions were tallied from two industry codes: F3200 (Accident & Health Insurance) and H3700 (HMO's). Data covers the 2004, 2006 and 2008 and 2010 campaign cycles. The fundraising data is adjusted based on the number of cycles that the senator has participated in as a Congressman (including time spent in the House of Representatives) or as a candidate, where 2010 is treated as 1/8th of a cycle since one quarterly report has so far been filed from the two-year period. So, for example, a senator that ran for and won office in 2006 is treated as participating in 2 1/8th out of a possible 3 1/8th cycles: 2006 as a candidate, and then 2008 and the fractional cycle in 2010 as a senator.”

Silver goes on to point out that: “Some 37 senators are listed by Howard Dean’s website as supporting the public option so far: 36 Democrats plus Olympia Snowe.  [So much for the theory that no Republican Senator would vote for the public plan—mm] To Dean's list I add Arlen Specter as a 'yes' vote, based on a recent public statement.

Silver then built “a model to explain and predict whether a particular senator supports the public option. The variables in the model are as follows:
— The senator's ideology, as measured by his DW-Nominate score. Click here  and scroll down to “most recently viewed pages” to find DW scores.

— Per capita health care spending in the senator's home state;

— Lobbying contributions received by the senator from health insurance PACs since 2004.
Using that model, he found that, “Lobbying contributions appear to have the largest marginal impact on middle-of-the-road Democrats. Liberal Democrats are likely to hold firm to the public option unless they receive a lot of remuneration from health care PACs. Conservative Democrats may not support the public option in the first place for ideological reasons, although money can certainly push them more firmly against it. But the impact on mainline Democrats appears to be quite large: if a mainline Democrat has received $60,000 from insurance PACs over the past six years, his likelihood of supporting the public option is cut roughly in half from 80 percent to 40 percent."

"(One caution: It's possible that we're confusing cause and effect: perhaps senators receive a lot of money from the insurance industry because they hold conservative positions on health care, rather than the other way around. Although I believe that accounting for ideology should correct for most of this, I'm open to suggestions on an alternative model design that would better be able to disentangle these effects.)

“Note that PAC money spent on Republicans is completely wasted insofar as the public option goes. Someone like Jim DeMint is almost certainly not going to support the public option to begin with; you don't need to give him any further incentive to oppose it! Of course, the insurance industry may get its money's worth in other ways, such as by generating more vigorous opposition from these Republicans to more "bipartisan" versions of health care reform.

“What happens if we set the lobbying variable to zero for all senators? That is, suppose that the health care insurance industry were prohibited from making political contributions? In that case, the model predicts, 47 senators would currently support the public option, as opposed to the 38 who actually do. In other words, 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.”

I’m not a political scientist, so I am not going to comment on Silver’s model. But I do find the numbers—and his analysis—fascinating.