WASHINGTON (AP) - The Supreme Court was sharply divided Wednesday in the latest challenge to President Barack Obama's health overhaul, this time over the tax subsidies that make insurance affordable for millions of Americans.

The justices aggressively questioned lawyers on both sides of what Justice Elena Kagan called "this never-ending saga," the latest politically charged fight over the Affordable Care Act.

Chief Justice John Roberts said almost nothing in nearly 90 minutes of back-and-forth, and Justice Anthony Kennedy's questions did not make clear how he will come out. Roberts was the decisive vote to uphold the law in 2012.

Otherwise, the same liberal-conservative divide that characterized the earlier case was evident.

Opponents of the law say that only residents of states that set up their own insurance markets can get federal subsidies to help pay their premiums. The administration says the law provides for subsidies in all 50 states.

The 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 the federal healthcare.gov. Giving subsidies only to people in some states would be "disastrous," Ginsburg said.

When Solicitor General Donald Verrilli Jr. stepped to the lectern, the liberal justices fell silent, and Justices Samuel Alito and Antonin Scalia took over.

"It may not be the statute Congress intended, but it may be the statute Congress wrote," Scalia said of the provision in question. The case focuses on four words in the law, "established by the state." The challengers say those words are clear and conclusive evidence that Congress wanted to limit subsidies to those consumers who get their insurance through a marketplace, or exchange, that was established by a state.

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Justices sharply divided over health care law subsidies