Senate attorneys scored a victory last week when the Supreme Court agreed to hear arguments over a lawsuit that would allow Congressional employees to claim workplace discrimination under the Congressional Accountability Act of 1995.

The Office of the Senate Chief Counsel for Employment is appealing an August decision by the U.S. Court of Appeals for the District of Columbia Circuit that allowed a discrimination lawsuit against former Sen. Mark Dayton (D-Minn.) to move forward. Senate counsel argued that Dayton is protected under the Constitution’s Speech or Debate Clause, which grants Members immunity for actions related to their official duties.

The court agreed to look at the case on Friday. Richard Salzman, who is representing former Dayton staffer Brad Hanson in the case, said he is not surprised by the court’s decision.

“It is an issue of first impression,” Salzman said. “It’s an important question that really challenges the statue.”

The Office of the Senate Chief Counsel for Employment did not return phone calls seeking comment.

Hanson originally sued Dayton in 2003. In the lawsuit, Hanson claims he was improperly fired by Dayton after he asked for time off to have cardiac surgery. Hanson specifically is suing Dayton for violating the Family and Medical Leave Act and Americans with Disabilities Act, as well as arguing Dayton violated the Fair Labor Standards Act by failing to pay him overtime.

Dayton repeatedly has denied the allegations.

Before that lawsuit can even proceed, the Supreme Court must decide if it can be heard. Salzman said that while he isn’t over-confident — there is no real precedent — he believes he has a strong case.

Salzman pointed to the decision in Forester v. White, in which the Supreme Court ruled a judge does not have immunity when he or she makes an employment decision because it is an administrative matter, not a judicial one.

Salzman said he will argue it is similar for Members of Congress, and Dayton’s immunity claim should not apply.

“It’s an argument that would leave every staff member for a Member of Congress unprotected by law,” Salzman said of Dayton’s claim. “The whole idea behind the law was to finally give people who work for Members of Congress the same rights as anyone else.”

Senate counsel is scheduled to file their briefs with the court in March, with Hanson needing to file in early April, Salzman said. He added that he expects the case will be heard by the court at the end of April.