It's a known fact that in the United States people are more easily controlled through their pocketbooks than through brute force. And what is more important and less cost-controllable than health care? Even without the "public option," it appears that the government will be setting billing guidelines, so it will have a direct impact on your pocketbook. With the public option or even the single-payer process, it would have complete control over your costs, and therefore much of your lifestyle.
Has anyone noticed the heightened concern over "obesity" becoming a "national health-care issue"? If you're overweight, you may have to pay more for your health care. But then there is the issue of how much red meat you eat, or if you smoke, or drink whole milk instead of soy milk, or if you own a gun, or the horsepower in your car, or even how many cars you own. Each of these (and an unlimited number of other factors) can certainly become a "health-care issue," and therefore a means to control your actions.
For many years, taxes have been used to control actions, like taxing cigarettes -- or, more recently, we see proposals to tax juices and sodas. Taxes are obvious to many people, but changing your health-care rates if you smoke is much more subtle.
Everyone seems to wonder why the administration isn't just working on the millions who don't have health care and is focusing on the entire population.