I am not certain what the answer to that question may be in total. It is interesting to ponder though as we see so many Republican bills for their own intervention into health care coming forth in 2009. I've counted nearly 40 GOP proposed health care bills, almost all of which increase government control and regulation, Republican style. Again, while to my knowledge none of the GOP proposed bills for intervention into health care allow a "public option" today, one must wonder if that would always be the case if they allow the intervention philosophically just as the Democrats. That is a surface difference only between the parties. A good example was the psychology of passing the Income Tax in 1913, the 16th Amendment. Part of the "sale" philosophically and psychologically was "don't worry, the rates are only 1%-7% and the only will hit the richest of the rich." That was true for a while as less than 1% of the population paid any income taxes that first year. It took an income of $500,000 in 1913 (over $10 million todays dollars) to trigger the top rate of 7%. Since its first seeminly innocuous passing though, tax rates have ranged as high as 90% and of course far more than 1% of the population pay taxes. So we can see with example after example that once the cat is out of the bag philosophically...
First, that both parties advocate government intervention and propose bills which redistribute wealth and empower government, we see again no root philosophical difference between the parties. If that were the case we should see the GOP standing up immediately and differing on base/root philosophical difference with the Democrats and pointing out the Constitution does not allow for Federal interference in health care market. As a starting point for considering the question of when the GOP sold out on health care I was curious what the vote was on the Medicare bill of LBJ's day. The question posed in the title of this post certainly deserves further research and consideration than laid out here. The official vote tally of the Act of 1965 surprised. Also surprising was that John Byrnes, a Republican from Wisconsin, was instrumental in the bill's authorship. Certainly the Democrats had strong majorities in both houses of Congress and LBJ was President. That said, I was shocked that essentially half of all Republicans already in 1965 were willing to vote for unconstitutional, interventionist legislation in the arena of health care. In fact the House GOP voted for it by 2 members, 70-68, with two not voting. The Senate GOP narrowly declined their consent to it, 13-17, with two not voting. While both major parties would probably love to have us continue to believe we should thank FDR and LBJ for health care intervention, they should thank long increasing numbers of the GOP.
Link to Medicare vote tally - 1965