Matt Skene has a very thoughtful post on the intersection of issues related to rights and obligations and recent health care debates. I disagree with a number of Matt's assumptions. I think we do have positive obligations, and I do think they simply are there without our taking them on. I don't think rights determine obligations but the other way around. Perhaps most salient, I don't think we can distinguish between obligations and moral goodness. I think we simply have an obligation to do what's morally best (and yes, I know that that means that pretty much everyone on this planet is thoroughly immoral, but that's not exactly a new view; it's historic Christian doctrine).
But I think there's a lot worth thinking about in Matt's post. His general approach is libertarian. He starts with natural negative rights and argues for no positive rights. In other words, certain things are wrong to do to me, because I have a right for you not to do them, but I have no rights for you to do positively good things on my behalf, just for you not to do bad things to me. But such a view doesn't imply that there aren't moral reasons to do positive things on behalf of other people.
In particular, there are reasons why it might be the morally best thing to do to help those who are less fortunate to obtain good medical care. Matt doesn't think I have an obligation to alleviate the suffering of people I have no other connection with, but he does think it's morally good to do so. It's also self-interestedly good for me to develop the character traits that such acts help develop in me. He's open to, but not convinced by, the argument that it would be in our best interests to contract with one another to institute such obligations by common consent, as we do with building highways. It depends on whether we'd all be better off with it.
Matt suggests an interesting possibility, though. You can donate money to your utility company to offset the costs of low-income utility customers. Presumably this goes to heating assistance aid, which is given to recipients of food stamps once a year and paid directly to the utility company. I'm not sure how else the utility companies would know who counts as low-income. But if we did a similar thing with insurance companies, there might be enough money from those who, like progressives on this issue, think they have an obligation to pay for others' insurance and from some of those who, like Matt, think it's a morally good thing to do. Could that cover everything Medicaid and other public health insurance does? It's worth seeing how much it covers.
I tend to doubt it, since most people who think the government should tax us more to pay for benefits to low-income people are not inclined to give money when it's voluntary (consider our current president as a prime example), but maybe enough people who don't share such views will give the money voluntarily while resisting it when it's government-controlled (as, apparently, Dick Cheney does with a huge percentage of his income). But it's being done with utilities. Why not try it with health insurance and see where it goes? There might even be enough votes in Congress after the 2010 election.