(The Center Square) – The 6th Circuit U.S. Court of Appeals Friday reinstated President Joe Biden's vaccine mandate on larger employees, overturning another federal court's injunction and setting up a showdown at the U.S. Supreme Court.

The mandate, depending on how the Supreme Court rules, would require employers with 100 workers or more to require their employees be vaccinated against COVID-19, undergo weekly testing, or face stiff fines.

“[I]t is difficult to imagine what more OSHA could do or rely on to justify its finding that workers face a grave danger in the workplace,” the 6th Circuit Court wrote.

OSHA, or the Occupational Safety and Health Administration, was charged with administering the workplace mandate.

The 5th Circuit U.S. Court of Appeals in New Orleans had previously blocked the mandate, citing "grave" constitutional concerns.

Several Republican state attorneys general, business and other groups filed lawsuits challenging the executive order. After the 5th Circuit halted the mandate, the lawsuits were consolidated and sent to the 6th Circuit. 

The latest ruling is sure to find itself before the U.S. Supreme Court.

"A bad decision by a left-leaning panel (Bush and Obama judges) of the 6th Cir.," Texas Attorney General Ken Paxton tweeted. "It’s un-American to force an unconst vax mandate on private biz, forcing people to choose b/w unemployment & an irreversible med procedure. I will immediately take this to SCOTUS to seek a reversal."