Washington - With the fate of President Obama's health care law hanging in the balance at the Supreme Court on Tuesday, a lawyer for the administration faced a barrage of skeptical questions from four of the court's more conservative justices.
"Can you create commerce in order to regulate it?" Justice Anthony M. Kennedy asked the lawyer, Solicitor General Donald B. Verrilli Jr., only minutes into the argument.
Justice Antonin Scalia soon joined in. "May failure to purchase something subject me to regulation?" he asked.
Chief Justice John G. Roberts Jr. asked if the government could compel the purchase of cellphones. Justice Samuel A. Alito Jr. asked about forcing people to buy burial insurance.
The conventional view is that the administration will need one of those four votes to win the case, and it was not clear on Tuesday that it had captured one.
The court's four more liberal members – Justices Ruth Bader Ginsburg, Stephen G. Breyer, Sonia Sotomayor and Elena Kagan – indicated that they supported the law, as expected. Justice Clarence Thomas, who asked no questions, is thought likely to vote to strike down the law.
Everything about the argument was outsized. It was, at two hours, twice the usual length. The questioning was, even by the standards of the garrulous current court, unusually intense and pointed. And the atmosphere in the courtroom, which is generally subdued, was electric.
The legal question for the justices was whether Congress had exceeded its constitutional authority in requiring most Americans to obtain insurance or pay a penalty. The practical question was whether Mr. Obama's signature domestic achievement would survive.
The law is the most ambitious piece of social legislation in generations. In attempting to deliver health care to tens of millions of Americans without insurance, it relied on a controversial mechanism at the center of Tuesday's arguments, the individual mandate.
Justice Ginsburg said the mandate was a response to the fact that uninsured people receive free health care that ends up being paid for by others. "They are making the rest of us pay," she said.
Justice Sotomayor said that Americans would not stand for a system in which children in danger of dying were turned away from emergency rooms.
But Justice Kennedy said the requirement to obtain insurance was unprecedented, giving rise to "a heavy burden of justification."
Mr. Verrilli responded that the health care market was unique and that regulating how people pay for services they are virtually certain to use at some point in their lives was well within the authority granted to the federal government by the Constitution, which gives Congress specified powers, reserving the rest to the states and to the people. The two powers at issue in the case, set out in Article I, Section 8, concern the regulation of interstate commerce and the imposition of taxes.
The administration's arguments concerning the tax power did not gain much traction, and most of the two-hour argument concerned the Commerce Clause, which gives Congress the power to regulate commerce "among the several states."
The question there, Justice Kennedy said, was whether there were "any limits" to Congressional power under the commerce clause, adding that he was concerned the health care law required individuals to perform "an affirmative act."
Justice Kennedy's questioning is famously hard to read, and near the end of the argument he noted that "most questions in life are questions of degree." But the great weight of his questioning was skeptical.
Justices Scalia and Alito were consistently hostile to the law, Chief Justice Roberts a little less so.
Asked about whether there were any limits on federal power under the commerce clause under the administration's theory, Mr. Verrilli noted two, in a somewhat convoluted answer. Congress has the authority to enact a comprehensive response to a national economic crisis, he said. And the health care law concerns only how who people bound to use health care will have to pay for it.
The Supreme Court has read the commerce clause broadly, saying it allows Congress to limit how much wheat may be grown on a family farm and to punish the cultivation of home-grown marijuana.
There have been only two modern exceptions to that broad interpretation. In 1995, the court struck down a federal law regulating guns near schools. In 2000, it struck down a federal law allowing suits over violence against women. In both cases, the court said the activity sought to be regulated was local and noncommercial.
On Tuesday, Paul D. Clement, representing the 26 states challenging the law, said none of those rulings contemplated requiring people to enter a commercial market.
Michael A. Carvin, representing private challengers, said that if the Supreme Court upheld the mandate, Congress would be free to regulate all human activity "from cradle to grave."