Ready To Rule

Justices including Stephen Breyer and Ruth Bader Ginsburg suggested they didn't view an 1867 law as barring them from ruling this year. Ginsburg questioned whether health-care penalties would be taxes.

"This is not a revenue-raising measure," Ginsburg said. "If it's successful, nobody will pay the penalty and there will be no revenue to raise."

The six hours of arguments spread over three days are the most the court has heard in a case in 44 years.

Tomorrow, the last day, the justices will consider what should happen to the rest of the law if they invalidate the insurance requirement. The court also will take up whether the law, by expanding the Medicaid program, unconstitutionally coerces states into spending more on health care for the poor.

The fate of the insurance requirement will turn partly on the court's interpretation of the constitutional provision that lets Congress regulate interstate commerce. Justices' opinions in previous cases only hint at how they may apply it to the insurance requirement.

Swing Votes

The justice who most often occupies the court's ideological middle ground, Anthony Kennedy, has signed opinions pointing in both directions on the commerce clause. Kennedy and three other Republican appointees -- Chief Justice John Roberts and Justices Antonin Scalia and Samuel Alito -- are potentially in play, based on their past opinions.

The government says that every American is already part of the interstate market for health-care and that the mandate requires them to get coverage to pay for treatment they'll eventually need. The challengers say Americans who fail to buy insurance can't be regulated because they aren't engaged in commerce.

"I'm sitting at home in my living room," said Michael Carvin, the lawyer who will argue on behalf of a business trade group, at a debate last month in Washington sponsored by Bloomberg Law and Scotusblog, which covers the court. "I'm not buying insurance. I'm not engaged in commerce -- local, intrastate, interstate. So how can they force me to enter into the stream of commerce?"