The National Treasury Employees Union’s argument that the government can’t force employees to work without pay during a government shutdown faced its first major hurdle Dec. 4, as the union and government went up against each other in a motion-to-dismiss hearing to argue whether the union has the standing to bring such a case before the court.

According to government attorneys, the union’s case — which claims that making government employees work during a government shutdown violates the Antideficiency Act and employees’ constitutional right to be compensated for their work — should be dismissed, because the court would be required to assume that the case is “capable of repetition,” or the exact same employees at the exact same agency would be impacted in the exact same way as they were in the 2018-2019 shutdown.

NTEU representation Paras Shah argued that only the legal result — that employees were forced to come into work without pay in the event of another shutdown — must occur to make their court case valid.

That argument comes down to whether a federal union should be treated as the same as any individual who brought that case or whether they can be treated as an association, and therefore must only prove that any of its members would be impacted in the same way in the event of another shutdown, rather than only the members that faced injury in the original shutdown and were featured in the case.

“Our legal injuries would occur on Day One in a lapse in appropriations,” Shah said, arguing that the many employees the union represents at 33 agencies and departments virtually guarantees that at least some of them would be impacted by a lapse in appropriations.

The case for NTEU, and indeed any other employee or organization that wanted to contest the legality of working during a shutdown, could be put in an impossible place if the court rules in favor of the government’s arguments. Legal precedent prevents such groups from bringing a lawsuit during a shutdown, as it would be too disruptive, but the government’s arguments would prevent lawsuits after a shutdown, as the plaintiff would be incapable of proving that another shutdown would definitely occur.

“Agencies, if left unchecked, would have little incentive to adhere to the Antideficiency Act,” said Shah.

The Trump administration drew harsh criticism during the last government shutdown, after it recalled IRS employees to process tax returns so that the impacts of the shutdown on the American people would be softened. Those employees’ jobs were largely not considered to fall under the general requirement that such employees be necessary for the safety of human life and the protection of property.

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The Government Accountability Office found that the IRS’s decision to recall over 30,000 employees back to work without pay in order to process tax returns was, in fact, a violation of the Antideficiency Act.

According to NTEU, the IRS can be expected to act in exactly the same manner during any future shutdowns that occur during tax season, as the agency presented the union with a revised shutdown plan that included such employees in those that would be required to work.

If NTEU’s case survives the motion dismiss and receives a favorable ruling in a full hearing, the decision could make any future government shutdowns significantly more damaging, as agencies would be prevented from requiring employees to work without pay, effectively stopping all government operations.

Such a ruling is unlikely to arrive in time to forestall a potential appropriations lapse this month, however.

Judge Richard Leon told attorneys for both the government and the union at the motion-to-dismiss hearing that they would be “lucky” to get an opinion on the case in January.

In the meantime, nearly the exact set of circumstances that created the last government shutdown look possible to reoccur, as funding for all government agencies is poised to lapse if Congress does not pass funding bills or a continuing resolution by Dec. 20. Republicans and Democrats also appear to continue to be at odds over whether such appropriations should provide funding for a wall at the U.S.-Mexico border.

Such a lapse may have the perverse effect of proving the NTEU argument in this case.

“It would show that our legal injuries are capable of repetition,” said Shah to reporters after the hearing.

The case itself comes with its fair share of irony: The Antideficiency Act was used in 1980 to justify why the government must shut down in the event of an appropriations lapse, rather than continuing to operate at past levels, as was done in years prior. Should the NTEU argument win out, that same act could be the very thing that could end future shutdowns.