In ruling on the constitutionality of requiring most Americans to obtain health insurance, the Supreme Court faces a central test: whether it will recognize limits on its own authority to overturn well-founded acts of Congress.

The skepticism in the questions from the conservative justices suggests that they have adopted the language and approach of the insurance mandate’s challengers. But the arguments against the mandate, the core of the health care reform law, willfully reject both the reality of the national health care market and established constitutional principles that have been upheld for generations.

The Obama administration persuasively argues that the mandate is central to solving the crisis in America’s health care system, which leaves 50 million people uninsured and accounts for 17.6 percent of the national economy. The challengers contend that the law is an unlimited — and, therefore, unconstitutional — use of federal authority to force individuals to buy insurance, or pay a penalty.

That view wrongly frames the mechanism created by this law. The insurance mandate is nothing like requiring people to buy broccoli — a comparison Justice Antonin Scalia suggested in his exasperated questioning of Solicitor General Donald Verrilli Jr. Congress has no interest in requiring broccoli purchases because the failure to buy broccoli does not push that cost onto others in the system.