So what has stopped the Republican administrations which have been in power on the States for most of the past 50 years from introducing a system of universal health care which didn't involve the problems they claim to see with the present proposals?

Is there a way of doing it that some other country has developed which would be acceptable to the opponents? If there isn't, given the enormous variety of countries involved, and the wide range of options, that if they can't it does appear to prove that the aim is, as Carol claimed, to stop any reform which would make adequate health care available to all Americans.