NEW ORLEANS — A federal agency erred in ordering Tesla CEO Elon Musk to delete a 2018 social media post that union leaders saw as a threat to employee stock options, a federal court has ruled. strongly divided call.

The case involved a post made on what was then known as Twitter during United Auto Workers organizing efforts at a Tesla facility in Fremont, California. The post was made years before Musk bought the platform, now known as X, in 2022.

On May 20, 2018, Musk tweeted: “There is nothing stopping the Tesla team at our car factory from voting to unionize. They could do that tmrw if they wanted to. But why pay union dues and give up stock options for nothing? Our safety record is 2x better than when the plant was UAW and everyone already gets medical attention.”

The National Labor Relations Board said it was an illegal threat. After Tesla appealed, three judges on the 5th U.S. Circuit Court of Appeals in New Orleans upheld that decision, as well as a related NLRB order that Tesla rehire a fired employee with back pay.

But Tesla sought a rehearing, and the full 5th Circuit later vacated its earlier decision and voted to hear the matter again. In an opinion dated Friday, the justices split 9-8 in favor of Tesla and Musk.

“We hold that Musk’s tweets are constitutionally protected speech and do not fall within the categories of unprotected communication such as obscenity and perjury,” the unsigned opinion said.

The majority also found that the NLRB must reconsider its order that the fired employee be reinstated, saying there was no evidence that the person who fired the worker acted in bad faith toward the union.

The 11-page opinion was followed by a 30-page dissent on behalf of eight justices, written by Justice James Dennis.

“Relevant here, the Supreme Court has consistently held that the First Amendment does not protect coercive and threatening speech by employers against employees in the context of labor organization elections — the exact category of speech Musk broadcast via Twitter,” Dennis wrote.

He also argued that the attitude of the supervisor who fired the worker is not relevant to reinstate him. The worker, Dennis wrote, “was fired for refusing to divulge information about protected union activities during questioning.”

The ruling sent the case back to the NLRB for further action. It was not immediately clear whether there would be an appeal to the US Supreme Court. The Associated Press sent an email to the UAW on Tuesday seeking information on the union’s next move.