I think there's a fascinating cultural difference between the way that Democratic politicians view the progressive base (as something to keep distance from, to be triangulated against) and the way Republicans view the conservative base (something to be paid regular tribute)
Lester Feder catches  an interesting example of this dynamic in action while talking to Chuck Grassley:
Rush Limbaugh, Fox News, and others recently launched a smear campaign against a provision in the stimulus bill designed to gather research that will help doctors and patients choose the treatments that work the best, and avoid unnecessary spending. This, said Fox, "appear [s]to set the stage for health care rationing for seniors, new limits on medical research, and new rules guiding decisions doctors can make about your health care."
At an event this morning at the Kaiser Family Foundation, I asked Senator Chuck Grassley (R-Iowa)--who, as the ranking minority member of the Senate Finance Committee, arguably has more influence on the fate of health reform than any other member of his party--whether such distortions from the right-wing noise machine will make it harder to get the bipartisan compromise he says he wants. Though the senator endorsed this kind of effectiveness research, he paradoxically also encouraged conservative commentators to keep doing what they're doing:
"I think they ought to hype them right now because people's attention needs to be brought to it, and that's the only way you're going to get their attention. When the dust settles, they won't have a leg to stand on and we will have and we will have a study and a tool that will be useful for doctors to use but not to dictate medicine."
In other words: it's politically beneficial for us to have propogandists who lie and distort the truth because it increases our room to politically maneuver.