Britain has true socialized medicine: 
The government provides health care directly through the National Health Service. 
Australia has a single-payer system, basically Medicare for All — it’s even called Medicare. 
But the Dutch have what we might call Obamacare done right: 
individuals are required to buy coverage from regulated private insurers, with subsidies to help them afford the premiums.

And the Dutch system works, which suggests that a lot could be accomplished via incremental improvements in the A.C.A., rather than radical change. Further evidence for this view is how relatively well Obamacare, imperfect as it is, already works in states that try to make it work 
https://www.nytimes.com/2017/08/07/opinion/healthcare-single-payer-children.html