Argument: Commerce clause does not authorize health insurance mandates
Congressional Research Service: "Despite the breadth of powers that have been exercised under the Commerce Clause, it is unclear whether the clause would provide a solid constitutional foundation for legislation containing a requirement to have health insurance. Whether such a requirement would be constitutional under the Commerce Clause is perhaps the most challenging question posed by such a proposal, as it is a novel issue whether Congress may use this clause to require an individual to purchase a good or a service."
Peter Urbanowicz and Dennis G. Smith. "Constitutional implications of an 'individual mandate'" Federalist Society: "If Congress were to invoke its Commerce Clause authority to support legislation mandating individual health insurance coverage, such an action would have to contend with recent Supreme Court precedent limiting unfettered use of Commerce Clause authority to police individual behavior that does not constitute interstate commerce: United States v. Lopez,10 invalidating the application of the Gun Free School Zones Act of 1990 to individuals and United States v. Morrison,11 invalidating certain portions of the Violence Against Women Act. In the case of a mandate to purchase health insurance or face a tax or penalty, Congress would have to explain how not doing something – not buying insurance and not seeking health care services – implicated interstate commerce."