BALTIMORE (CN) – A union of federal government workers is challenging the Trump administration’s restrictions on political speech, claiming they not only violate the First Amendment, but could prevent federal employees from doing their jobs.

In a suit filed in federal court in Maryland Tuesday, the American Federation of Government Employees claims the Office of Special Counsel has misinterpreted the Hatch Act – the law prohibiting federal employees from politicking on the job – so confusingly that federal employees could be afraid to report waste, fraud and abuse.

“This case concerns an unprecedented attempt to stifle the speech of public employees on matters of the utmost public concern – whether the President is fit to remain in office and whether his Administration’s policies serve the best interests of the country,” the complaint states.

Under the current interpretation of the Hatch Act, federal employees – including OSC’s own members who served under Robert Mueller – “could be punished for, in the view of many, recommending that Congress commence impeachment proceedings against the President,” the complaint states.

“Of course this is absurd,” it adds.

The federal employees’ union represents more than 600,000 federal workers. R. Stanton Jones of the Washington DC firm Arnold & Porter Kaye Scholer is listed as the lead attorney for the group.

The case stems from a November 2018 email, and subsequent clarification, published by the Office of Special Counsel to advise federal employees what they can and cannot do under the Hatch Act. The Office of Special Counsel is supposed to protect federal employees from reprisals for whistleblowing, and is headed by a presidential appointee, Henry Kerner, who previously worked for both the late Senator John McCain and California Representative Darrell Issa.

A spokesman for the office said Tuesday that they could not comment on pending litigation.

At the heart of the matter is whether impeachment is a political issue, which can be freely discussed under the Hatch Act, or a part of a political campaign, which cannot.

Federal employees found in violation of the Hatch Act can be fired.

The OSC’s Nov. 30 “clarification” letter stated that, because President Trump was running for reelection, and because successful impeachment bars a person from running for office, advocacy of impeachment is necessarily a prohibited political act.

The letter also banned federal employees’ use of the #Resist hashtag, calling it a Democratic Party slogan.

Impeachment does not automatically bar a person’s running for election, the complaint notes. That requires a separate vote in the Senate and has seldom been done.

More fundamentally, the complaint alleges, the OSC’s conflation of talk of impeachment with political activity strikes at the heart of federal employees’ oath of office.

“Indeed, the Advisory Opinion and the Clarification impermissibly expand the definition of prohibited ‘political activity’ to infringe on important legal obligations imposed on federal employees to identify waste, fraud, and abuse in government and to fulfill their oaths of office to uphold the Constitution,” the complaint states.

Federal employees are required by law to swear an oath to defend the Constitution, and the Office of Government Ethics requires them to disclose all abuse and corruption to authorities, according to the complaint.

“OSC’s Advisory Opinion and Clarification purport to supersede these authorities and punish federal employees for commenting on the most severe possible infractions – treason, high crimes, or misdemeanors by the President,” the complaint states.

The union also alleges that OSC should not be allowed to prohibit federal employees from using #Resist, and that OSC has improperly determined that use of the hashtag necessarily equates to criticism of a political campaign.

“That is, what began as resisting President Trump and his policies while in office – which is permissible under the Hatch Act – has become automatically resisting candidate Trump in his quest for reelection – which is prohibited under the Hatch Act.”

The OSC has been inconsistent, according to the complaint.

“At nearly the same time OSC issued the Advisory Opinion, it cleared members of the Trump Administration of alleged violations of the Hatch Act for using the term ‘MAGAnomics,’” the complaint states. “‘MAGA’ is short for ‘Make America Great Again,’ which is the official slogan of the Trump campaign.”

The plaintiffs seek a declaratory judgment that OSC’s interpretation violates the First Amendment or, at least, that government employees can use the word “resist” and advocate for or against impeachment.