Using the same analysis we did last time, only predicting vote share rather than polling results, we find that Democratic House members who voted for health care reform did an average of 5.2 percentage points worse than those who voted against it. This effect is statistically significant. This is controlling for district partisanship and the members' ideal points (an estimation of their overall voting record).
Suffice it to say this is a huge effect. As it turns out, of the 41 House Democrats we examined,
Conversely, we find that five Democratic members who did get reelected would be out of a job today if they'd voted yes on health reform. These include Altmire (PA), Chandler (KY), Matheson (UT), McIntyre (NC), and Shuler (NC).
We ran the same analysis for two other controversial votes, the stimulus and cap-and-trade. We found no statistically significant effect for either of those votes. (This is somewhat different from Eric McGhee's findings, so Eric, Steve, and I will need to hammer this all out over beers in Chicago next April.)
Some caveats: This does not include the entire Democratic caucus -- just the 41 members from the 50 most conservative Democratic-held districts who were running for reelection. We'll expand our analysis on this soon. It also doesn't control for spending, although most analyses I've seen on that suggests the effect was kind of a wash.
I've done some previous reflection on how to interpret the fact that Democrats finally following through on a longstanding party commitment appears to have hurt them dearly. For more on this, I'd suggest reading Jonathan Bernstein, who suggests that delivering on this goal was worth losing an election over. I still maintain that health reform will be popular and untouchable, along the lines of Social Security, in the coming decades, but we're not there now. It's currently unpopular. If it were popular, it would have happened a long time ago. Instead, what it took was a determined and (relatively) unified party with sizable majorities in both chambers. Going against public opinion is a big part of what strong parties do, and it's not surprising that there's occasionally a large price to be paid.