Einer Elhauge, professsor of law and founding director of the Petrie-Flom Center in Health Law Policy at Harvard University, says there are limits to Congressional powers under the Commerce clause such as enacting a law requiring Americans to eat broccoli. If the health care law required all Americans to subject themselves to health care this would be the case. But the law only requires all to buy insurance so that insurance can cover the costs of healthcare for all. He points to the "necessary and proper clause" as also authorizing the health care mandate. That clause gives Congress the power to pass laws that are "rationally related" to execution of constitutional powers, such as criminalizing the interference with mail, on the basis of the constitutional power to setup post offices. In this case the health care law mandate is related to the constitutional power to regulate premiums and prohibit rejecting the sick, says Elhauge.