President Biden dared Republicans to "have at it" and sue over his new vaccine requirements.
A new federal regulation will mandate vaccines or testing for employers with 100+ workers.
Biden announcing the new requirement sparked backlash and threats of lawsuits from GOP figures.
See more stories on Insider's business page.
President Joe Biden dared Republican governors and lawmakers to sue his administration over newly unveiled vaccine mandates after speaking at Brookland Middle School in Washington, D.C. on school reopenings.
"Have it at," Biden told a reporter who asked him about potential legal challenges to the administration's new, wide-ranging COVID-19 vaccination requirements.
Biden took a firm and assertive tone in a Thursday address announcing a slew of new federal government requirements and mandates to combat the Delta variant and boost lagging vaccination rates, explicitly laying the blame on unvaccinated Americans and some GOP leaders.
In addition to a stricter vaccination requirement for federal employees and contractors, Biden announced his administration will implement new regulations under the auspices of the Department of Labor requiring public and private sector employers with over 100 employees to mandate their employees get vaccinated or submit to regular testing.
The Labor Department is set to draft an emergency temporary standard, or ETS rule, creating the requirement, which will be enforced by the Occupational Safety and Health Administration, or OSHA. The announcement immediately sparked fierce backlash from Republican governors, members of Congress, and conservative media figures.
"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 on Friday. "We're playing for real here. This isn't a game."
While Biden hasn't singled out specific governors, he could be referring to Gov. Greg Abbott of Texas and Gov. Ron DeSantis of Florida, who have taken particularly aggressive action to curb local governments, school districts, and private businesses from mandating masks and vaccinations.
Legal challenges to the new Biden administration regulation would likely center around whether OSHA can legally impose such a requirement under the federal government's authority to regulate interstate commerce, vaccine law expert Brian Dean Abramson told Insider.
Governmental vaccine mandates, more broadly, stand on strong legal footing in the history of US jurisprudence. In the 1905 Supreme Court case of Jacobson vs. Massachusetts, the high court ruled against a man who sought exemption from Cambridge's smallpox vaccine mandate.
In addition to the new public private-sector vaccine mandates, Biden announced a vaccine requirement for healthcare providers that receive federal funds, a new partnership with the private sector to increase testing capacity in schools, and expanding access to COVID-19 treatments.