Center for American Progress has always been in favor of government-run single payer. Obamacare is just a big giveaway to Grrrrreeeedy Eeeeeeeevil Insurance Companies in their view.
Re pre-existing conditions: Insuring them is just like insuring a barn that is already burning. It is a money losing proposition.
It is also a moral hazard to permit people to wait to insure until the barn is afire.
However, if you require all barns to be insured from the moment of construction, then the moral hazard disappears.
Translating this to human beings, it means that you have to insure everyone from womb to tomb. (yes that includes the unborn babies).