(Bloomberg) -- The U.S. Supreme Court delivered a fresh reminder of its power to thwart President Joe Biden’s agenda as it sided with Republicans by blocking a rule that would have required Covid-19 vaccinations or weekly testing for more than 80 million workers.

The court’s conservative majority on Thursday dealt a dramatic blow to the centerpiece of Biden’s strategy for increasing the nation’s vaccination rate, ruling in favor of business groups and 27 mostly GOP-led states in an expedited case.

It’s the second time the court had stymied a Biden effort to stem the virus’s spread, following a decision in August to lift an eviction moratorium the administration said would keep people from being forced into tighter living quarters. In both cases, the court pushed back against the power of the executive branch and said it needed clear approval from Congress to allow an action with such broad economic and political implications.

“This decision should be a loud wake-up call to those who think the Biden administration’s agencies can unilaterally create sweeping, unprecedented powers in old, limited statutes,” said Adam White, a senior fellow at the American Enterprise Institute who served on the commission Biden appointed to evaluate proposals to reform the Supreme Court.

The court, which has a 6-3 Republican-appointed majority, is becoming a formidable obstacle for Biden. Without a working majority in Congress -- Democrats control the Senate only because of Vice President Kamala Harris’ tie-breaking vote -- the president has had to rely on administrative agencies to implement his policy goals.

Asylum and Climate

That approach, now being challenged aggressively by business interests and states with Republican governors or attorneys general, is bumping up against a court inclined to keep a tight rein on those agencies. In August the court rejected the administration’s bid to rescind a Trump-era policy that requires asylum seekers at the southern border to wait in Mexico for their cases to be processed.

And the justices next month will hear a far-reaching case that could curb the Environmental Protection Agency’s ability to address climate change through broad reductions on power-plant emissions.

“This Supreme Court is on a mission to remake the regulatory state,” said Lawrence Gostin, faculty director of the O’Neill Institute for National and Global Health Law at Georgetown University Law Center. “The conservative majority is willfully trying to make it hard, if not impossible, for the federal government to safeguard the public’s health and safety, including worker safety, safe food and drugs, and environmental protection.”

In a decision that came over the dissents of the three liberal justices Thursday, the court said the Occupational Safety and Health Administration exceeded its authority in requiring employers with 100 or more workers to make them get vaccinated or be tested regularly, potentially at their own expense. 

“Although Congress has indisputably given OSHA the power to regulate occupational dangers, it has not given that agency the power to regulate public health more broadly,” the court said in an unsigned opinion. 

The court backed the administration Thursday on a separate rule, allowing a vaccine mandate for workers in nursing homes, hospitals and other facilities that receive federal Medicare and Medicaid payments. Chief Justice John Roberts and Justice Brett Kavanaugh joined the liberals in the majority.

But that rule will affect only about 10 million workers, making it a relatively small piece of the vaccination push Biden announced Sept. 9.  

Biden said in a statement he was disappointed the court blocked “common-sense life-saving requirements for employees at large businesses that were grounded squarely in both science and the law.” He said it was now up to states and private employers to determine whether to institute such requirements to keep their workplaces safe.

The Supreme Court had been receptive to targeted vaccine mandates issued by state and local officials, repeatedly rejecting religious objections. But the OSHA case centered not on religious rights but on the power of a federal agency whose governing statute doesn’t explicitly authorize vaccine requirements.

The health-care vaccination rule, issued by the Centers for Medicare & Medicaid Services, was challenged by separate groups of states led by Missouri and Louisiana. In permitting that rule, the court by a 5-4 majority said Congress had authorized the agency to take steps to protect the health and safety of Medicaid and Medicare recipients. 

Three of the dissenters in the health-care clash laid down a marker in the OSHA case. Justice Neil Gorsuch, in an opinion joined by Justices Clarence Thomas and Samuel Alito, touted a pair of legal principles, known as the major questions doctrine and the non-delegation doctrine, the court has at times used to curb what agencies can do without explicit authorization from Congress.

“The question before us is not how to respond to the pandemic, but who holds the power to do so,” Gorsuch wrote. “The answer is clear: Under the law as it stands today, that power rests with the states and Congress, not OSHA.”

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