A federal court in Missouri has blocked the Biden administration from enforcing a coronavirus vaccine mandate for health care workers at federally funded facilities in 10 states.

Why it matters: Monday's decision is the first victory for opponents of the rule, which requires health care workers to get vaccinated by Jan. 4, 2022. The case is one of four lawsuits challenging the Centers for Medicare & Medicaid Services' (CMS) rule and argues that the mandate will exacerbate staffing shortages.

What he's saying: The mandate exceeds the agency's authority, U.S. District Judge Matthew Schelp wrote in the opinion.

• "The nature and breadth of the CMS mandate requires clear authorization from Congress—and Congress has provided none," he said.
• Along with its "political significance," the cost of compliance with the mandate — around $1.38 billion in the first year — represents the "heavy hand of the federal government," he added.
• "[E]ven if Congress’s statutory language was susceptible to CMS’s exceedingly broad reading — which it is most likely not — Congress did not clearly authorize CMS to enact the this politically and economically vast, federalism-altering, and boundary-pushing mandate, which Supreme Court precedent requires."
• Missouri, Nebraska, Arkansas, Kansas, Iowa, Wyoming, Alaska, South Dakota, North Dakota and New Hampshire are not subject to the mandate as the case moves forward, so long as the preliminary injunction remains in place.

Worth noting: Courts have generally upheld COVID vaccine mandates in recent months, with the Supreme Court declining to block enforcement of Maine's requirement for health workers.

• The Biden administration's vaccine mandate for large companies has, however, faced some pushback.

What to watch: If the administration appeals the injunction, it would go to the Eighth Circuit. Over half of U.S. states are involved in one of the four legal challenges, according to Bloomberg Law.

• "We're obviously going to abide by the law and fight any efforts in court or otherwise to prevent local authorities, officials, leaders in the health care industry and other industries from protecting their workforces," Press Secretary Jen Psaki said in a White House briefing on Monday.

Go deeper: Republican-led states begin legal fight over Biden vaccine mandate