Military veterans are sworn in during a naturalization ceremony at a Veteran's Day event at Fort Sam Houston National Cemetery, Thursday, Nov. 11, 2021, in San Antonio. Credit: Eric Gay / AP

The Biden administration’s push for vaccine mandates, under fire in courts around the nation, has survived a legal challenge headed by former Trump campaign lawyer Sidney Powell over vaccines in the military.

Powell, who tried to flip the result of the 2020 presidential election with a series of failed lawsuits based on conspiracy theories, lost a request to temporarily block the Pentagon’s COVID-19 vaccine mandate. The lawsuit was filed on behalf of disgruntled service members.

The suit didn’t come close to meeting the high bar for winning a preliminary injunction, U.S. District Judge Allen Winsor ruled Friday in Pensacola, Florida.

The ruling is a crucial early victory for the U.S. Defense Department. A ruling against the U.S. also would have been a blow to President Joe Biden, whose broader vaccine mandate for companies with at least 100 employees was temporarily blocked a week earlier by a federal appeals court in a suit by Republican-led states.

“The plaintiffs have not met their extraordinary burden of showing the mandate lacks any rationality,” Winsor, an appointee of former President Donald Trump, said in the ruling.

The suit, which also names the Food and Drug Administration, was filed in October by Powell’s Dallas-based nonprofit group Defending the Republic. Powell had requested a court order blocking implementation of the mandate but also undoing the FDA’s full approval of the Pfizer Inc.-BioNTech SE vaccine.

The judge ruled the plaintiffs were unlikely to succeed in their claim that Defense Secretary Lloyd Austin’s Aug. 24 requirement is invalid because it wasn’t vetted by mandatory public comment. The Pentagon issued the rule a day after the FDA granted full approval for the Pfizer vaccine, supplementing an earlier emergency use authorization.

The service members who sued — from states across the U.S. including Alaska and Florida — accused the FDA of approving the vaccine only to appease Biden, who has made mandates central to the fight to end the pandemic.

“On the merits, the plaintiffs haven’t made a substantial showing that the FDA acted without a reasonable scientific basis,” the judge said. “The FDA is entitled to substantial deference.”

Story by Erik Larson.