Protesters rally outside the Theodore Roosevelt Federal Building headquarters of the U.S. Office of Personnel Management on Feb. 5, 2025, in Washington, D.C.

As thousands of federal workers agonize over whether they should try to keep their jobs or submit to an unprecedented resignation push from President Trump, a legal battle is quickly taking shape, adding another complicated layer to an already chaotic situation.

Federal workers originally had until midnight on Thursday to decide whether to take a deferred resignation offer from the Trump administration. Around 60,000 workers had reportedly resigned as of Thursday afternoon, around 3% of the federal workforce, according to NBC News. After a court challenge, however, a federal judge in Boston instituted a temporary order against the offer today, and the deadline will be extended to Monday, pending a separate court hearing.

That lawsuit came from federal worker unions, and demands that the Office of Personnel Management (OPM) and acting director Charles Ezell vacate the resignation directive and “provide a reasoned basis” for issuing such an offer.

As federal workers and the American public wait to see what happens next, experts tell Fortune that the legal future looks messy, and that the fight ahead between the Trump administration and federal workers may go all the way to the Supreme Court.

Unclear directives

The original resignation offer email sent to federal workers last week, headed “Fork in the Road,” was both remarkable and unclear.

Federal employees Fortune previously spoke with say that they and their colleagues were deeply confused by the offer itself, as well as a follow-up FAQ released by the OPM. They added that they had little to no help from their agency superiors when it came to how they should weigh their options. “People need to know how little we’re getting from management, how blind we are,” said one federal patent office worker.

More broadly, however, it’s unclear if the president even has the authority to make such an offer—that’s what a coalition of unions are suing over.

The legal fight

A legal challenge to the OPM’s resignation offer was filed this week by four organizations: the American Federation of Government Employees AFL-CIO; the American Federation of Government Employees AFL-CIO Local 3707; the American Federation of State, County and Municipal Employees AFL-CIO; and the National Association of Government Employees.

“Despite claims made to the contrary, this deferred resignation scheme is unfunded, unlawful, and comes with no guarantees,” AFGE National President Everett Kelley wrote in a statement accompanying the suit.

Those groups are arguing that the Administrative Procedures Act, the law that regulates government agencies, bars actions that are “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with the law.” They also argue that the resignation offer is illegal due to its promise to pay workers with money that hasn’t yet been appropriated by Congress.

What happens now?

After Thursday’s court-ordered stay, a court hearing is now scheduled for Monday, during which the plaintiffs and the Trump administration will make their case.

But no matter what happens, the fate of federal workers won’t be decided in one fell swoop. “That’s not the end of the litigation,” says Tom Spiggle, a lawyer who specializes in employment law and workers’ rights.

On Monday, if the judge sides with the plaintiffs, he can issue an injunction against the OPM which would bar it from implementing the resignation offer. If the government appeals, there will be a hearing for a permanent injunction. And only then will there be a trial on merit, says Spiggle.

Peter Rahbar, a leading employment lawyer for the Rahbar Group, adds that right now, the case is in district court. The next stop would be the circuit court, and then possibly even the highest court in the land. “I assume this will be taken all the way up to the Supreme Court,” says Rahbar.

If the courts side with the federal worker unions, experts say, the Trump administration will have a much harder time executing on its stated goal of shrinking the federal workforce. Most federal workers are harder to cut than their private-sector counterparts, says Rahbar. The majority have a right of notice depending on how long they’ve served in government, have appeal rights, and can demand documentation about why specifically they will be laid off, he says, adding that there are also union collective bargaining rules to consider.

“Federal workers are hard to fire. They have rights that private-sector workers do not have,” he says. “And frankly, I think that’s why a lot of government employees are comfortable rejecting this.”