We do have Medicare which could be argued as a form of Universal Health Care, and honestly it is a cluster fuck, it is abused, doctors are starting to refuse to take it now, etc etc. And mind you just because other developed democratic nations have it, does not make it a good thing. One could argue that the NHS is a terrible system in Britain, and as we are seeing in Greece right now, their Universal Health Care system is on the verge of complete destruction because of their debt.
Are there good systems out there? Of course, but you have the basic fear that any system implemented here will be either
A: Completely like Medicare and have the same problems.
B: Have some of the big wait times and problems seen in Canada or Britain
C: Something that could leave the citizens screwed if the Government is forced to start cutting back.