Court sharply divided over care subsidies.

Byline: Mark Sherman

WASHINGTON -- Sharply divided along familiar lines, the Supreme Court took up a politically charged new challenge to President Barack Obama's health overhaul Wednesday in a dispute over the tax subsidies that make insurance affordable for millions of Americans.

The outcome in what Justice Elena Kagan called ''this never-ending saga'' of Republican-led efforts to kill the Affordable Care Act appears to hinge on the votes of Chief Justice John Roberts, whose vote saved the law three years ago, and Justice Anthony Kennedy.

Roberts said almost nothing in Wednesday's 85 minutes of lively back-and-forth, and Kennedy, who voted to strike down the health law in 2012, asked questions of both sides that made it hard to tell where he might come out this time.

Otherwise, the same liberal-conservative divide that characterized the earlier case was evident in the packed courtroom with the same lawyers facing off as in 2012.

Millions of people could be affected by the court's decision. The justices are trying to determine whether the law makes people in all 50 states eligible for federal tax subsidies to cut the cost of insurance premiums. Opponents say that only residents of states that set up their own insurance markets can get federal subsidies to help pay the premiums.

Roughly three dozen states did not set up their own exchanges and rely on the federal healthcare.gov. The Obama administration says it would make no sense to condition subsidies on where people live, and that doing so would set off a ''death spiral'' in which enrollment declined, driving premiums up and leaving only the sickest, and costliest, people insured.

Liberal justices peppered lawyer Michael Carvin almost from the outset of his argument to limit the subsidies.

Justice Ruth Bader Ginsburg said the law set up flexibility for states to either set up their own markets or rely on federal healthcare.gov. Giving subsidies only to people in some states would be ''disastrous,'' she said. ''I have never seen anything like this.''

Several justices tried to use Carvin's comments from the 2012 case that seemed to cut against his argument Wednesday.

Finally, Roberts gently came to his defense. ''Mr. Carvin, we've heard talk about this other case. Did you win that other case?'' Roberts said as laughter washed over the courtroom. ''So maybe it makes sense that you have a different story today?''

When Solicitor General Donald Verrilli Jr. stepped to the lectern, the liberal...