I'm not sure that any version of a national health care system - existing, proposed by President Obama, or otherwise - is going to truly meet the needs of every U.S. citizen. As I've said about our approach to supporting the elderly in our culture, I think there are ways to approach true care for health and well being that focus on community and local/regional resources instead of nationally calibrated insurance premiums and risk formulas.
But if we accept for a moment that people in this country will probably continue to obtain medical services via some kind of national insurance system for the foreseeable future (and coldly put aside the many millions of people without even that benefit right now), then we need to talk about the practice of insurance rescission.