Besides, other products are much more important in sustaining human life than health care. With a good physical constitution you can live for decades without a doctor; you cannot survive more than a few days without water. Food too is essential, much more essential than medicine. Moreover, if failure to buy health care insurance bears on interstate commerce, so does eating hamburgers instead of broccoli, and this is so even if it subsequently turns out (as has happened many times in the history of nutritional advice) that eating broccoli is bad for you.

The question that the authors ask is whether the Commerce Clause in the Constitution “authorizes Congress to require individuals to buy products that Congress thinks they should buy to further the general welfare.” To search for a sharp line of demarcation between what legislators may and may not legitimately do has baffled the minds of political philosophers for centuries; but there is no doubt that, left to their own devices, most politicians would like to make you eat up your greens.