Andrew Gelman, Nate Silver and Daniel Lee in the NYT:
We’ve crunched some poll numbers in order to relate senators’ positions on the bill to public opinion in their home states. First, we rated each of the 100 senators from 1 to 5, based on their public statements and their committee votes on the health care initiative, with 1 meaning completely opposed (like Jim DeMint of South Carolina) and 5 meaning completely supporting the bill (like Barbara Boxer of California).
We then compared these scores against several statistical indicators that would presumably affect lawmakers’ positions, including their party affiliations and the rate of uninsurance in their home states. We also looked at polling data from the National Annenberg Election Surveys, which asked voters in each state: “Providing health insurance for people who do not already have it — should the federal government spend more on it, the same as now, less, or no money at all?” (The Annenberg data are from 2000 and 2004; 2008 data have yet to be released.)
But the relationship between state-level opinion and senators’ positions on health care disappears once we introduce another variable — Mr. Obama’s margin of victory in each state in 2008. This holds whether or not we take into account a senator’s political party.
For instance, Senator Blanche Lincoln, a Democrat who has been a less-than-strong supporter of the present health care bill, recently told The Times, “I am responsible to the people of Arkansas, and that is where I will take my direction.” But where does she look for her cue? Hers is a poor state whose voters support health care subsidies six percentage points more than the national average. On the other hand, Mr. Obama got just 40 percent of the vote there.