Part of the answer, according to Rasmussen, is that Democrats strongly approve of single-payer. Democrats support single-payer at the rate of 62%. In contrast, Republicans reject single-payer at a rate of 87%, while those not affiliated with either party reject single payer by a 63-22% margin. The lesson here, I think, is that single-payer is a terrific "wedge" issue.
John C. Drew, Ph.D. is an award-winning political scientist.