Judge Jeffrey Brown, who was appointed by former President Trump, wrote that the order exceeded the president’s authority.
The case is about “whether the President can, with the stroke of a pen and without the input of Congress, require millions of federal employees to undergo a medical procedure as a condition of their employment,” Brown wrote.
The Department of Justice immediately said it would appeal.
The order comes after the Supreme Court earlier this month blocked Biden’s mandate that employees at businesses with 100 or more workers get vaccinated or regularly tested, while upholding the vaccination mandate for health care workers.
The federal government’s power to mandate vaccination for its own employees is thought to be on stronger legal footing, though Friday’s ruling underscores the ongoing nature of the dispute.
“I’m sorry, but this is just insane,” Steve Vladeck, a law professor at the University of Texas, wrote on Twitter. “The federal government lacks the power to require its *own* employees to be vaccinated?”
Judge Brown pointed to the interest in “maintaining the liberty of individuals to make intensely personal decisions according to their own convictions.”
Republicans have mounted a major legal campaign against Biden’s vaccine mandates and have denounced them for infringing on people’s personal choices.
Many health experts have praised the mandates as a step towards getting more people vaccinated, a crucial step in protecting against severe illness from COVID-19.
After the mandate for large employers was struck down earlier this month, Biden urged businesses to impose mandates for their workers on their own.