With the potential to affect up to 100 million Americans, or nearly two-thirds of the country’s labor force, President Joe Biden’s new vaccine requirements are being met with predictable opposition from a handful of Republican states, who have become a new front in the battle between the government and local authorities over how to address the ongoing pandemic.

Fact-Check: Are Vice President Biden’s Vaccination Requirements ‘Illegal’?

A number of Republican state leaders have already said that they plan to fight the vaccination requirement even though the exact regulations governing it have not yet been established. A lawsuit against Vice President Joe Biden and other members of the administration on the basis that the vaccination requirements are “unconstitutional” was filed on Tuesday by the state of Arizona’s attorney general.

Are Vice President Biden's Vaccination Requirements 'Illegal'

State Republicans such as South Dakota Gov. Kristi Noem and Georgia Gov. Brian Kemp have blasted the requirements as “gross examples of federal interference.” In contrast, South Dakota Gov. Kristi Noem has blasted them. As “blatantly illegal overreach.”

Aiming to boost vaccination rates, Biden ordered the Labor Department last week to compel all companies with 100 or more employees to demand that their workers be either vaccinated or checked for Covid-19 every week as part of his effort to increase immunization rates. The proposed vaccination requirement has received widespread support from major business organizations such as the United States Chamber of Commerce.

There has also been supporting for the requirement from the AFL-CIO and a number of other major labor organizations. Still, there has been some resistance from police enforcement organizations, some of whom are concerned about how Biden plans to execute his proposal.

As a result, Biden’s proposal depends on the Department of Labor’s authority to establish “a temporary emergency norm” to protect workers from new dangers, so long as the employees in question “are subjected to severe danger,” and the standard “is required to safeguard” them from the danger. The Occupational Health and Safety Act of 1970 gives the government this authority.

That power, on the other hand, is seldom used, and past cases have been successfully contested in the courts. According to a July 2021 study from the Congressional Budget Office, this power has not been used since 1983, when the courts knocked down an emergency interim asbestos regulation that had been issued by the Environmental Protection Agency.

Healthcare workers who are at greater risk of exposure to Covid-19 were protected by an emergency interim standard established by the U.s. Occupational Safety And Health, a regulatory body under the Department of Labor, in June 2021.

According to legal experts who spoke, Biden’s order and OSHA’s new emergency interim norm may face a difficult battle in the coming months. According to labor and employment expert Brett Coburn of Alston & Bird LLP, whether or not the new requirement is legal “will rely on how OSHA verbalizes the ‘grave risk’ in issue here, as well as how the courts that will hear the inevitable challenges interpret the case.”The power of OSHA to impose an interim emergency norm, according to Josh Blackman, a constitutional law professor at South Texas College of Law who specializes in the constitution, is less certain in light of the present circumstances.