So I've been thinking about the whole "broccoli" argument with regard to the supreme court. Basically it goes like this: If the federal govt can force someone to buy health insurance, why can't they force someone to buy broccoli or anything else? Kennedy and I think SAcalia both asked this and wanted a limiting principle to government power here, and Verrilli couldn't answer it in my opinion. So here's my take.
I'm not a lawyer, but can't you limit the congressional power here using a combination of the necessary and proper clause and legitimate interests test? Congress clearly has the power to regulate the medical insurance market as interstate commerce. the ACA, minus the mandate, creates a broad set of regulations including the pre-existing condition rule. if that rule is enforced, the insurance market will fail due to free riders who only get insurance when they are sick. thus congress has a legitimate interests in public health and safety to find a means to fix this problem and maintain a functional health insurance market. the mandate is necessary and proper to accomplish this legitimate interest. thus congressional power is limited in 2 ways, with respect to forcing people to "buy brocolli".
1) buying and eating eating brocolli may make people healthier but its not necessary to maintaining a functional market. just having people be a bit healthier is not a legitimate government interest.
2) the insurance market is unique. It has perverse incentives which do not exist in most (any?) other markets; because consumers are driven to not purchase until they are sick and providers are driven to cover only those who are not sick and unlikely to become sick. Also we have specific laws guaranteeing medical coverage which induces direct cost shifting from non-insurance holders to insurance holders. And finally, virtually everyone will participate in the medical care and insurance market in their lifetime and be unable to afford the care without insurance.