The U.S. Supreme Court heard arguments in a high-stakes public session to decide whether the U.S government can begin enforcing sweeping COVID-19 vaccine requirements affecting nearly 100 million workers.

For three hours and 40 minutes, the justices heard oral arguments over federal vaccine and testing rules for businesses with 100 employees or more, and on vaccine mandates for health care workers at facilities receiving Medicaid and Medicare funding.

The Biden administration tried to enforce vaccine mandates but the high court halted it saying it will make a decision whether to allow the Biden administration can go ahead with the mandates or not, based on its findings on the current hearings.

At a Supreme Court hearing on President Biden’s vaccine mandates on health services that receive Medicaid and Medicare funds, Justice Clarence Thomas questioned Missouri Deputy Attorney General Jesus Osete.

In early arguments, Chief Justice John Roberts and Justice Neil Gorsuch suggested that government officials had overstepped, with Roberts declaring that it is “hard to argue” that officials had been given the power to act by Congress.

Justice Brett Kavanaugh also noted that Congress had yet to pass any type of vaccine statute. Justice Amy Coney Barrett questioned Elizabeth Prelogar Solicitor General of the United States, who was arguing for OSHA’s vaccine mandate.