The "fork in the road" has some very sharp prongs

• The lawsuit echoes and expands upon the opinion of legal experts who believe the deal — offered to federal workers only last week in an email with the subject line "a fork in the road" — is illegal.

How it works: If an employee resigns by Thursday, they can go out on administrative leave through September 30 and still get paid, according to materials sent out by the Office of Personnel Management, the federal government's HR department.

• The agency's guidance over the past week has evolved and expanded, as criticism of the program has grown.

Where it stands: The lawsuit alleges a "scattershot approach," arguing that the changing guidance has made it even more difficult for federal employees to weigh such an important decision in such a short amount of time.

• The deal was accompanied by "implicit threats" of termination, the lawsuit claims, noting that the fork email made clear that federal agencies were likely to face downsizing: "Employees are advised if they forgo the offer — even with all of this attendant lack of clarity — they risk unemployment."
• OPM said it doesn't comment on pending litigation.

The other side: Senior officials from the department insisted to Axios on Monday, before the suit was filed, that the offer is lawful as an option for workers who want an "off-ramp" from the upheaval around President Trump's restructuring efforts.

• They issued a memorandum on Tuesday, titled "Legality of Deferred Resignation Program," expanding on their reasoning.

State of play: Lawyers and other critics say the deal is unlawful and workers who take it risk getting stiffed.

• "Completely illegal," said David Super, a professor at Georgetown Law, whose research focuses on administrative law.
• "Any federal official signing this contract would be subject to criminal penalties on the antideficiency law," he added. (More on that below.)
• "Do I think President Trump would prosecute such people? No, but most people prefer not to violate criminal laws," said Super, who earlier in his career was general counsel for the progressive Center for Budget and Policy Priorities.
• Super said one possibility is that workers don't get paid the full term of the deal, then file lawsuits, only for a court to rule the deal was unlawful. They'd then be out of luck.

Zoom in: There is a provision of federal law — 5 USC 6329a — that limits administrative leave for federal workers to 10 days in a calendar year. The Trump deal is for eight months.

• The intention behind the law was to avoid spending large amounts of public dollars on people who aren't working, Super said.
• The "fact is, neither Musk nor even Trump has legal authority to offer you eight months of pay if you'll resign by February 6," outspoken progressive and former labor secretary Robert Reich wrote last week.

The other side: Officials at OPM pointed Axios to a memo the department issued on Trump's first day in office that says agencies have discretion to offer more leave. (More of their response here.)

There is also the pressing matter of March 14, when the government could shut down if the debt ceiling isn't raised. Funding for federal agencies is not guaranteed after that.

• Another federal law, the Antideficiency Act, holds that federal agencies can't promise to spend money in excess of what Congress has made available, the Wall Street Journal notes. (The union lawsuit cites this law.)
• The offer to pay workers through September also "appears to violate this statute," Nicholas Bednar, a law professor at University of Minnesota, told the paper.
• An agency spokesperson disputed that the deal violates this law.

The big picture: The resignation offer is part of the Trump administration's broader purge of the federal workforce and, like many of the president's orders so far, it's testing the law to an unprecedented degree.

Where it stands: Only 20,000 workers, less than 1% of the federal workforce, have taken the deal so far, Axios' Marc Caputo scooped Tuesday morning. (The federal workforce's normal attrition rate is about 6% a year.)

• The ones who took the deal are those who were already planning to leave, said Sheria Smith, president of a local branch of the American Federation of Government Employees that represents 2,800 workers at the Education Department.
• "Mainly, they had other job offers. This could be a windfall for them," she told Axios. She also noted that many of her union members have been placed on administrative leave by the White House for reasons that are unclear to them.