https://www.pewresearch.org/fact-tank/2020/09/29/increasing-... ("Pew Research: Increasing share of Americans favor a single government program to provide health care coverage (2020)"
https://www.pewresearch.org/fact-tank/2018/10/03/most-contin... ("Pew Research: Most continue to say ensuring health care coverage is government’s responsibility (2018)"
I won't pollute the thread by bloating this comment with large citations, but both links are interesting reads as to who falls where on the spectrum.
That argument is this: first look at the history - why is it that health care is so expensive?
I (well not I, but scholars of this bent) argue some of the reasons for that are (a) price and wage controls during ww2 leading to employers subsidizing health care as a way to increase real wages while sticking to the letter of the law, so to speak, and this becoming a “sticky” practice leading to a general divorce of payee and payer in the health care system, as more and more people get employee subsidized insurance, and thus allowing prices to get distorted as the signal was hidden behind the subsidy, and meanwhile (b) the AMA, restricting the supply of doctors, bolstering their prestige, and wages. Etc etc
Just talking from the point of view of the price system, meaning nothing against people with other arguments for the existence of the ama.
So, if health insurance removes the direct price signal from health care provider to health care recipient, prices rise for years, and the problem festers and grows worse as politicians punt it down the road...
Finally we come to the universal health care system as the answer. In this light it may be seen as a further divorce of payee and payer, such that cost will rise over the long time horizon, or effectiveness per dollar will drop, etc.
On the other hand the public private quagmire that arose as a result of insurance company protectionist land grabs and back room deals between employers and insurers did no favors for outcomes under the present system. Anybody try a high deductible health plan this decade? What shit. It’s so bad that likely a universal system will be an improvement, even from this vantage.
On the other hand, perhaps you'd get better replies if you started with a better question. Nobody is "against health care for all". Nobody would "vote against the idea that everyone is healthy".
A better question is: Should the US federal government (continue to) ensure that some level of health care is provided for all, and what level is that?
"None" is an extremist answer; would you abolish the Emergency Medical Treatment and Active Labor Act, which requires most hospitals to treat any person in mortal need who shows up?
"All" is the other extreme, although it's unclear whether it's an "extremist" answer if there are real countries that have implemented federally guaranteed "best-effort all health care for all". Which I don't know enough to answer. Do those places exist?
Anyway, I think that's a better starting point for the conversation.