From the medical perspective(Im a surgeon) the concern at most large academic centers regarding nationalized health care is the loss of research drive. If you look at a lot of medical literature, the vast majority originates from the United States, with a significantly smaller percentage coming from the EU and then Japan. The belief is that all large academic centers fight over NIH grants by pursuing cutting edge research in medicine, whether this is really necessary or not, e.g. do we need better resolution CT scanners is questionable, nevertheless the research technology trickles to the rest of the world. So part of the concern over nationalized health care is a loss of research drive since there would a loss of competition among academic institutions. Personally I don't think nationalized health care is the solution, though I believe a baseline level of health care should be provided to all in the form of primary prevention, (vaccination for babies, etc) and then if anybody wants to pay for more, go for it...I think this is similar to the system used in Japan...