A federal appeals court on Thursday cleared the way for President Trump to keep using the National Guard to respond to immigration protests in Los Angeles, declaring that a judge in San Francisco erred last week when he ordered Mr. Trump to return control of the troops to Gov. Gavin Newsom of California.

In a unanimous, 38-page ruling, a three-judge panel of the U.S. Court of Appeals for the Ninth Circuit held that the conditions in Los Angeles were sufficient for Mr. Trump to decide that he needed to take federal control of California’s National Guard and deploy it to ensure that federal immigration laws would be enforced.

The panel — made up of two appointees of Mr. Trump and one of former President Joseph R. Biden Jr. — rejected a lower-court judge’s conclusion that the protests were so unruly that they could trigger a rarely-used law that Mr. Trump invoked when he claimed the power to federalize the National Guard over Mr. Newsom’s objections.

“Affording appropriate deference to the President’s determination, we conclude that he likely acted within his authority in federalizing the National Guard,” the court wrote, in an unsigned opinion on behalf of the entire panel.

The ruling was not a surprise. During a 65-minute hearing on Tuesday, the panel’s questions and statements had telegraphed that all three judges — Mark J. Bennett, Eric D. Miller and Jennifer Sung — were inclined to let Mr. Trump keep controlling the Guard for now, while litigation continues to play out over California’s challenge to his move.