WASHINGTON (AFP) - The US Supreme Court on Thursday upheld a disputed portion of President Barack

Mr Obama's landmark health care reform, in a major legacy-building victory for his administration. By a margin of six to three, the judges ruled in favor of allowing the federal government to subsidize health insurance by giving tax credits to consumers nationwide.

Opponents of the Affordable Care Act - better known as "Obamacare" - had argued that it was unconstitutional for the federal government to subsidize insurance.

More than six million Americans who signed up for policies through exchanges set up in states that did not set up their own could have lost their coverage, but the judges ruled that the law should stand.

"This is a victory for common sense and for all American families," declared Ms Nancy Pelosi, leader of the Democratic minority in the House of Representatives.

"It is long past time for Republicans to abandon their assault on the newfound health security that the Affordable Care Act is providing millions and millions of Americans across the country."

Republicans reacted angrily. "Republicans will continue to fight tooth and nail to repeal this oppressive law," declared Senator John Cornyn, the party's number two leader in the senate.

"Today's decision doesn't change the fact that Obamacare has been a disaster for the millions of hardworking American families who have seen their health care costs skyrocket or lost their insurance entirely."