Sen. Joe Manchin (D-W.Va.) has come out against President Joe Biden’s unprecedented private sector vaccine mandate, joining Republicans in officially cosponsoring a bill that would overturn the rule.

Manchin indicated that he was considering just such a move early Thursday afternoon.

“I’ve been very supportive of the mandate for federal government, for military, for all the people that work on government payroll,” he told reporters. “I’ve been less enthused about the private sector.”

“We’re working through it,” Manchin said noncommittally.

Later the same day, Manchin announced that he had made his decision, saying that he would support Republicans in their effort to strike down the private sector mandate.

Manchin noted in a Thursday evening statement, “I have personally had both vaccine doses and a booster shot and I continue to urge every West Virginian to get vaccinated themselves.” Still, the senator emphasized his opposition to any effort to impose vaccination on private sector employers and employees.

“Let me be clear: I do not support any government vaccine mandate on private businesses,” said Manchin. “That’s why I have cosponsored and will strongly support a bill to overturn the federal government vaccine mandate for private businesses.”

“I have long said we should incentivize, not penalize, private employers whose responsibility it is to protect their employees from COVID-19,” Manchin said.

Manchin’s commitment to join Republicans comes amid a concerted GOP effort to overturn the private sector mandate.

All Republicans in the upper chamber joined with Sen. Mike Braun (R-Ind.) and Senate Minority Leader Mitch McConnell (R-Ky.) on Nov. 18 to challenge the measure under the Congressional Review Act (CRA).

The CRA, approved in the 1990s under Speaker of the House Newt Gingrich, allows Congress to review and, if necessary, to overturn new federal regulations put into place by federal administrations such as the Occupational Safety and Health Administration (OSHA). If a rule is overturned under this procedure, federal administrations are forbidden from issuing the same or a substantially similar rule.

Under the rules of its charter, a CRA motion can be passed by a simple majority, without the risk of a filibuster.

Biden introduced his sweeping vaccine mandate in September, telling the nation that “our patience is wearing thin” with the millions of Americans who have chosen to not get vaccinated against the CCP (Chinese Communist Party) virus.

The mandates would apply to all federal employees, including military personnel and federal contractors. They would also extend into the private sector, requiring that all firms with 100 employees or more mandate vaccination or weekly testing for the virus.

To enact the mandates, Biden asked OSHA to declare an emergency temporary standard. In the past, such standards have been used to guard employees against dangerous chemicals or other similar toxins.

OSHA said in a statement to The Epoch Times that the emergency temporary standard would “ensure [that a firm’s] workforce is fully vaccinated or require any workers who remain unvaccinated to produce a negative test result on at least a weekly basis before coming to work.”

In total, Biden’s mandate would extend to roughly 100 million Americans, nearly a third of all U.S. citizens.

However, the legal maneuvering Biden used to reach into the private sector is subject to a litany of rules and restrictions that could cause the OSHA rule to be shut down.

Foremost among these is the CRA motion, which would not only overturn OSHA’s temporary emergency standard, but would prohibit the imposition of another substantially similar rule.

The mandate also faces challenges in the court system; Already, the conservative-leaning 5th Circuit Court has challenged Biden’s authority over the health decisions of private sector employees and employers.

Referencing Biden’s “thinning patience,” 5th Circuit Court of Appeals Judge Kurt D. Engelhardt wrote that to protect “our constitutional structure … the liberty of individuals to make intensely personal decisions according to their own convictions—even, or perhaps particularly, when those decisions frustrate government officials”—must be upheld.

States have also challenged the rule through a slew of avenues, including an effort to expand unemployment eligibility to those who lost their job due to refusal to take the vaccine.

A coalition of 24 state Attorneys General have also challenged the motion, promising to take advantage of “every available legal option to hold [Biden] accountable and uphold the rule of law.”

Manchin’s defection comes amid these increasing challenges to Biden’s diktat, and gives Republicans a much better shot at overturning the unprecedented mandate.