Over at the Tenth Amendment Center, University of Montana law professor Rob Natelson argues that esteemed constitutional scholar Akhil Reed Amar is wrong about the constitutionality of the health care mandate:
Amar: "Under the interstate commerce clause of Article I, activities whose effects are confined within a given state are to be regulated by that state government, or simply left unregulated. But the federal government is specifically empowered to address matters that have significant spillover effects across state lines or international borders."
Natelson: The interstate commerce clause gave Congress power to regulate interstate commerce — not any "matters that have significant spillover effects across state lines." The Constitutional Convention rejected the wording of the Virginia Plan, which arguably would have let the federal government regulate any activity with interstate spillover. Instead, the delegates limited Congress to enumerated powers, such as the power over interstate commerce. The Bill of Rights constricted those powers further.
In other words, the Founders made the deliberate decision to leave many activities with spillover effects to the states. They also included a qualified state power to deal with spillover effects by interstate compact. The Founders knew that through "sophistry" (their word) one can always claim a spillover effect, so giving the federal government power over anything with significant spillover effects would result in no real constraints on the federal government at all.
Amar: "[T]he founders authorized Congress to act even in situations that did not involve explicit markets, so long as the activities truly crossed state lines or national borders."
Natelson: Under the Commerce Clause, Congress received the power to regulate "Commerce." Several scholars, including I, have published research showing what the Constitution meant by this word. Based on over two thousand uses of "commerce" in Founding-Era records, we know that the word meant mercantile trade and certain closely-related activities, such as marine insurance and navigation, traditionally governed by the rules pertaining to merchants. "Commerce" did not include other economic or non-economic activities.