Mark Robbins, acting chairman of the U.S. Merit Systems Protection Board and the only appointed person remaining on the board, with some of the backlogged case files earlier this month in Washington. (Bill O'Leary/The Washington Post)

Federal workers will have to wait indefinitely for their claims of mistreatment to be heard after lawmakers continued to sideline the small agency that hears employment grievances.

Two of the three seats on the Merit Systems Protection Board have been open for two years, and the third board member leaves Feb. 28.

A Senate committee approved two of President Trump’s three nominees to the board. A third nominee, whose qualifications were questioned by lawmakers in both parties, was pushed to withdraw from consideration before the panel met Wednesday.

Sen. Ron Johnson (R-Wis.), chairman of the Senate Homeland Security and Governmental Affairs Committee, said he would not advance the two endorsed nominees to the Senate floor until the president nominates and the committee supports a third member. That won’t happen before the lone current board member leaves in two weeks.

The board, which hears appeals of firings, demotions, suspensions and alleged misconduct, has a backlog of more than 1,900 cases. Even if a new board were appointed soon, it could take two years to eliminate the backlog.

Once the lone board member leaves, the quasi-judicial agency of 240 employees will conduct business with no one at top, an unprecedented and potentially illegal turn of events for an executive branch agency, experts have said. Mark Robbins, the board’s lone member, said Justice Department attorneys told him in the fall that the board could be forced to disband without a governing board. The agency declined to comment.

Advocates for federal employees called the delay unconscionable and said the Senate should confirm the two board members who made it out of committee before Robbins leaves so the agency can function.

“The board has been without a quorum for over two years, meaning no decisions . . . and no relief or certainty for federal employees or federal agencies, and a historic backlog,” said James Eisenmann, a former executive director of the board who now represents federal employees in private practice. “It’s time for the Senate to confirm the two board nominees so federal employees can receive the due process to which they are entitled.”

The board, with eight regional offices, lost its quorum when Trump took office in January 2017. Trump didn’t nominate a new board for more than a year, and then the Senate committee deadlocked last year on his picks.

Administrative judges have held hearings and issued decisions on employees’ complaints. But any appeals of those rulings — whether by employees or agencies — to the three-member board have not been decided. Robbins has written judgments and set them aside for new board members to agree or dissent. But if no board member arrives before he leaves, his opinions will be discarded.

“This situation is appalling, but not shocking,” said Kristin Alden, another attorney who represents federal workers. “Congress has the power and opportunity to mitigate this egregious situation by appointing the two remaining nominees. It’s unconscionable that thousands of federal employees are suffering because Congress will not do the right thing.”

The board could still function with two members. If they split on an appeal, the decision of the administrative judge would stand. But Johnson said at Wednesday’s hearing that the Senate prefers to vote on nominees to bipartisan boards “en bloc.”

Two House Democrats — Rep. Elijah E. Cummings (Md.), chairman of the Oversight Committee, and Rep. Gerald E. Connolly (Va.), both with large concentrations of federal employees in their districts — introduced a bill Thursday that would continue Robbins’s term for an additional year. His term already has been extended by a year.

But Trump tapped Robbins in December as acting general counsel at the Office of Personnel Management, and he is likely to stay there. Robbins declined to comment.

The committee on Wednesday approved by voice vote Republican Dennis Kirk to serve as board chairman and Democrat Julia Clark as a member. The only senator in opposition was Rand Paul (R-Ky.), who said he opposes the merit systems board in principle, calling it a “job protection board.”

Andrew Maunz, a Republican, withdrew his name after unions that represent federal employees criticized his management in his previous role leading the Social Security Administration’s Office of Regional Counsel.