After Obama appeared to question the role of the courts in reviewing the two-year-old law, which seeks to expand healthcare coverage to 30 million-plus uninsured Americans, a conservative Texas judge on the Fifth Circuit Court of Appeals ordered the administration to explain itself.

Attorney General Eric Holder told the appeals court in a three-page letter that the power of courts to review the laws "is beyond dispute" and that the administration has not sought to limit or reconsider that principle.

He argued that when courts do consider such challenges, precedent dictates that "Acts of Congress are 'presumptively constitutional'" and that the executive branch often urges courts to respect such laws passed by Congress.

"The president's remarks were consistent with the principles" described in the letter, Holder said.

Obama on Monday said he did not believe the Supreme Court would take the "unprecedented, extraordinary step" of overturning the 2010 law and questioned whether the court would be engaging in judicial activism if it indeed struck it down.

That drew swift criticism from conservatives who questioned whether he was trying to send a message to the justices and whether he understood that the courts did have a role in reviewing whether laws Congress passes are constitutional.

Obama, White House aides and administration officials have since tried to clarify and soften the tone, acknowledging that the courts have a responsibility to review such laws but insisting the president only meant the court has rarely struck down laws on national economic issues.

The president's initial remarks prompted Judge Jerry Smith of the 5th Circuit Court, an appointee of Republican President Ronald Reagan, to demand clarification about the courts' role in reviewing laws during separate arguments this week on the healthcare law, a rare courtroom response to outside remarks.

On Thursday, lawyers for hospitals challenging the healthcare law asked the appeals court for an opportunity to respond to Holder's letter, saying in a filing that it advanced the government's position in the case and warranted a response.

While unusual for a president to weigh in on a Supreme Court review after the arguments, academics have said that opponents of the healthcare law had been outspoken and Obama was within his rights to do the same.

"To be clear, there is absolutely nothing wrong with the president saying this. Why might the president do this? It is an election year," said Erwin Chemerinsky, dean of the University of California, Irvine law school. "If the court strikes down the law, this will be the message. He is getting it out now."

Randy Barnett, a Georgetown University law professor involved in the constitutional challenge to the healthcare law, declined to comment directly on Obama's remarks.

But as a general matter, he said, "It is wrong to accuse the Supreme Court of acting politically simply because some justices disagree with how you think the precedents apply to a case ... like this one."

To read the letter, click here: here

(Reporting By Jeremy Pelofsky and James Vicini; Additional reporting by Terry Baynes; Editing by Cynthia Osterman and Paul Simao)

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