The Obama administration argued to the U.S. Supreme Court this week that people must be compelled to buy medical insurance (designed by the government) or the national medical-insurance market will fail. Thus, Obamacare advocates say, the insurance mandate is consistent with the powers delegated under the Commerce Clause of the U.S. Constitution. The argument, however, contains a fatal flaw. If the medical-insurance market would indeed fail without a mandate, writes Sheldon Richman, it's only because of other mandates the government has already imposed. Thus the government has created the rationale for an extension of its own power.