Biden welcomes GOP challenges to his vaccine mandate: 'Have at it'

President Joe Biden on Friday welcomed a legal challenge from several Republican governors to his sweeping and constitutionally dubious federal vaccine and testing requirements.

"Have at it," the president said.

Biden spoke at a middle school in Washington, D.C., where he and first lady Jill Biden were visiting to talk about his administration's efforts combat the Delta variant in schools with mandatory testing. His comments came in response to a question from ABC News reporter Rachel Scott about many Republican governors who have called his mandates an "overreach" and have threatened to sue the administration to block the vaccine mandates on private businesses from taking effect.

"I am so disappointed that particularly some Republican governors have been so cavalier with the health of these kids, so cavalier with the health of their communities," Biden said.

"One of the lessons I hope our students could unlearn is that politics doesn't have to be this way," he continued. "They're growing up in an environment where they see it's like, like a war, like a bitter feud. ... It's not who we are as a nation. And it's not how we beat every other crisis in our history."

Biden announced Thursday that he would sign an executive order requiring companies with more than 100 employees to mandate vaccinations or have their workers submit to weekly testing requirements. The new federal requirements are part of a larger six-point plan to combat the Delta variant of coronavirus, after his administration's previous efforts to get Americans vaccinated failed to deliver on the promised result of a return to normal.

Several Republican governors immediately vowed to fight what they say is an unconstitutional attack on personal liberties.

The president, meanwhile, insisted Friday that governors and school districts implement vaccine requirements to protect children from the virus.

"We all know if schools follow the science — like they are here — and implement safety measures like vaccinations, testing, masking, then children can be safe in schools safe from COVID-19," Biden said.

The Food and Drug Administration has not yet approved vaccines for children younger than 12, a fact that Biden recognized. He promised that the FDA is working "as safely and as quickly as possible" to learn if the vaccines are safe for children and urged parents with children older than 12 to get them vaccinated.

"The safest thing you can do for your child 12 and over is get them vaccinated," Biden said, adding that vaccination requirements in schools are "nothing new."

"You got them vaccinated for all kinds of other things — measles, mumps, rubella — for them to go to school, to be able to play sports, they've had to have those vaccinations," Biden said. "It is safe, and it's convenient, and we'll work to bring the vaccine clinics to our schools as well."