* Analysis says law could add up to $530 bln to deficit
* White House criticizes former Bush official's report
* Obama administration says law will better control costs
By John Crawley
WASHINGTON, April 10 (Reuters) - Instead of curbing government spending, President Barack Obama's healthcare law could add up to $530 billion to the federal debt over ten years, a Republican expert on U.S. government benefit programs said on Tuesday.
A study by Charles Blahous, a George Mason University research fellow and the Republican trustee for the Medicare and Social Security entitlement programs for the elderly, challenged the administration's contention that the 2010 law would reduce healthcare costs.
But the Obama administration defended the law as a cost-saver and sharply criticized the report by Blahous, an economic policy adviser under former President George W. Bush.
Known as the "Affordable Care Act," or by conservatives as "Obamacare," the measure to expand health insurance for millions of Americans is considered Obama's signature domestic policy achievement.
The Supreme Court is weighing whether Congress overstepped its authority to regulate commerce in approving the law. The justices heard arguments in the high-stakes case two weeks ago.
Republican presidential candidates have promised to repeal the law if one of them wins the White House in the November election. Conservatives denounce the sweeping overhaul as an unwarranted government intrusion.
Obama and the Democrats believe the law will control skyrocketing costs and curtail government "red ink."
White House health adviser Jeanne Lambrew said Blahous' analysis wrongly charges that some savings are "double counted." She said government estimates from the Office of Management and Budget and from the non-partisan Congressional Budget Office show the 2010 law would lower federal deficits over a 10 year period.
"This new math fits the old pattern of mischaracterizations about the Affordable Care Act when official estimates show the health care law reduces the deficit," Lambrew, deputy assistant to the president for health policy, wrote in a blog post on the White House website.
But Blahous, who also served as the deputy director of the National Economic Council under Bush, said in his research that the law is expected to boost net federal spending by more than $1.15 trillion and add between $340 billion and $530 billion to deficits between 2012-21.
"Relative to previous law, the (healthcare law) both exacerbates projected federal deficits and increases an already unsustainable federal commitment to health care spending," he concluded.
The analysis, first reported by the Washington Post late on Monday, also comes a month after the Congressional Budget Office cut the estimated net cost of the healthcare law by $48 billion to $1.08 trillion through 2021.