A few points about health-care reform
1) The national health systems in use in other countries vary widely in the quality of care they provide and in the degree of satisfaction that their people have with them. It's important not to rush into an ill-conceived plan here which, if implemented, might be worse than the situation we have now, when a more carefully-designed reform would produce better results. It's also important to avoid putting all our eggs in the basket of a plan which would risk rejection by the public. Any proposal under consideration needs to have a realistic chance of being enacted, or it's pointless.
2) Most things that work well, work well because of the element of competition -- if the customer can take his business elsewhere, the provider has an incentive to do a good job. Any national health plan must keep the element of competition between providers. Even if there's a single (governmental) payer, there need to be competing service providers and the ability of patients to switch from one to another to maintain the incentive for performance. The best way to do this would probably be a voucher system. Remember that while 15% of the population lacks insurance, 85% do have it, and they won't support (or allow their representatives to support) a reform which leaves them with less choice than they have now.
3) A question which will need to be addressed: Will the publicly-funded health plan serve illegal aliens? If it won't, we'll need to finally create some national system for distinguishing citizens and legal residents from illegal aliens. If the national health plan will serve illegal aliens, public opposition will prevent it from ever being implemented in the first place. A plan that spends taxpayer money to cover people who aren't even supposed to be in the country is a non-starter. It would be too unpopular. It would even risk handing the Republicans an issue they could use to revive their fortunes.