Is Opinion Shifting On Health Care?

This Associated Press-GfK poll on health care has gotten a great deal of media attention. Here is how the AP characterizes its own findings:

As lawmakers shaken by the shooting of a colleague return to the health care debate, an Associated Press-GfK poll finds raw feelings over President Barack Obama’s overhaul have subsided.
Ahead of a vote on repeal in the GOP-led House this week, strong opposition to the law stands at 30 percent, close to the lowest level registered in AP-GfK surveys dating to September 2009.
The nation is divided over the law, but the strength and intensity of the opposition appear diminished. … The poll finds that 40 percent of those surveyed said they support the law, while 41 percent oppose it. Just after the November congressional elections, opposition stood at 47 percent and support was 38 percent.
As for repeal, only about one in four say they want to do away with the law completely. Among Republicans support for repeal has dropped sharply, from 61 percent after the elections to 49 percent now.

It appears that what is mostly going on is that the AP-GfK sampled a heavily Democratic group of respondents this month. This is on top of the fact that the survey sampled all adults, not likely voters. Here is the history of AP-GfK’s polling over recent months. Note that the really significant difference is that between likely voters (as measured in October 2010) and all adults. Click to enlarge:
Now look at who was being surveyed in the latest AP-GfK poll, compared to earlier surveys:
Democrats and Democrat leaners outnumbered Republicans and Republican leaners by six points, whereas among likely voters in October, Republicans outnumbered Democrats by the same margin. It stands to reason that if you over-sample Democrats, you will get poll data more sympathetic to their policies.
Meanwhile, in a Rasmussen poll that came out this morning, support for repeal of Obamacare “remains steady” at 55-40 percent:
The principal difference between this Rasmussen survey and the AP-GfK poll is that Rasmussen surveys likely voters.
It is reasonable to assume that Democrats in the press have deliberately promoted the AP-GfK poll in order to deter Republicans from voting for repeal and to encourage Democrats to stick with the administration. It will be interesting to see whether today’s Rasmussen survey gets an equal amount of media attention.