Attorney General Eric H. Holder Jr. Thursday defended President Obama’s comments urging the Supreme Court to uphold the health-care law, telling a panel of federal judges that courts should show “deference” to the “legislative judgements of Congress.’’

Holder, responding to an unusual demand for his views on whether federal judges have the authority to strike down federal laws, affirmed that they have such authority. “The power of the courts to review the constitutionality of legislation is beyond dispute,’’ he wrote in a letter to the U.S. Court of Appeals for the 5th Circuit in New Orleans.

But the attorney general, citing a series of Supreme Court and other cases, said acts of Congress are presumed to be constitutional and should be overturned only sparingly. “The Supreme Court has often acknowledged the appropriateness of reliance on the political branches’ policy choices and judgements,’’ Holder wrote before concluding: “The President’s remarks were fully consistent with the principles described herein.’’

The pointed response was the latest step in an intense debate surrounding the fate of the health-care law, Obama’s signature domestic accomplishment. Conservative Supreme Court justices appeared open to declaring the heart of the legislation — which requires uninsured Americans to buy health-care coverage — unconstitutional in their recent review of the law.

Obama struck back Monday, saying that overturning the law would be an “unprecedented, extraordinary step” of judicial activism. Many conservatives were outraged by his comments, but White House officials have called them unremarkable.

The unusual presidential observations provoked a response from Judge Jerry Smith, a Republican appointee on the 5th Circuit. Citing Obama’s statements, he demanded on Tuesday a letter from Holder explaining whether federal judges can strike down federal laws.

Smith, part of a panel of three Republican appointees hearing arguments in a lawsuit over the Affordable Care Act, said the letter must be three pages. Holder’s response fell short: It was about 21 / 2 pages.

And, in an apparent critique of the judge’s order, he noted: “The question posed by the court . . . does not concern any argument made in the government’s brief or at oral argument in this case.’’

Smith declined to comment.