WASHINGTON (AP) -- The Supreme Court on Thursday upheld the nationwide tax subsidies underpinning President Barack Obama's health care overhaul, rejecting a major challenge to the landmark law in a ruling that preserves health insurance for millions of Americans.

The justices said in a 6-3 ruling that the subsidies that 8.7 million people currently receive to make insurance affordable do not depend on where they live, as opponents contended.

The outcome was the second major victory for Obama in politically charged Supreme Court tests of his most significant domestic achievement. And it came the same day the court gave him an unexpected victory by preserving a key tool the administration uses to fight housing bias.

Obama greeted news of the decision by declaring the health care law "is here to stay." He said the law is no longer about politics, but the benefits millions of people are receiving.

Declining to concede, House Speaker John Boehner of Ohio said Republicans, who have voted more than 50 times to undo the law, will "continue our efforts to repeal the law and replace it with patient-centered solutions that meet the needs of seniors, small business owners, and middle-class families."

At the court, Chief Justice John Roberts again voted with his liberal colleagues in support of the law. Roberts also was the key vote to uphold it in 2012. Justice Anthony Kennedy, a dissenter in 2012, was part of the majority on Thursday.

"Congress passed the Affordable Care Act to improve health insurance markets, not to destroy them," Roberts declared in the majority opinion.