The Supreme Court heard arguments Tuesday in a case that will decide whether Capitol Hill staffers have the right to claim workplace discrimination against lawmakers under the Congressional Accountability Act.

The court’s decision will determine if a discrimination lawsuit against former Sen. Mark Dayton (D-Minn.) can move forward. The one-term Senator is being sued by former staffer Brad Hanson, who alleges that he was improperly fired after taking time off to have heart surgery.

Mirroring arguments presented in lower courts, 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.

In her 30-minute argument, Senate Chief Counsel for Employment Jean Manning focused on the role Congressional staffers play as a Member’s “second self,” meaning they take on roles that Members cannot always fill themselves.

“Therefore, they are an integral part of the legislative process of the Member’s office,” Manning said. “For that reason, the Member must have absolute trust and confidence that these employees are in fact performing as his ‘second self,’ and to do that, the Member has to have complete discretion in selecting who these employees are and in managing them.”

But in their questioning, several justices asked Manning if her interpretation of the clause could allow Members to have protection over actions that do not involve legislative functions.

Justice Stephen Breyer pointed specifically to Hanson’s job duties, pressing Manning on whether his responsibilities even covered any legislative functions.

“What does he do? He seems to spend a lot of time moving furniture,” Breyer said. “He lists that twice. He runs the office. And … he is out in the local office somewhere and he talks to constituents. I mean, he doesn’t even appear in the Senate office except very rarely, in which case he is doing casework.”

Manning responded that about 5 percent of Hanson’s duties did involve legislative work. She cited his involvement in preparing Dayton for a hearing on medical care conditions in Minnesota, something Hanson brought up because his job required him to meet with constituents regularly.

Manning also added that the very act of hiring and firing should be considered under the clause, as it involves a legislative function.

“When the Member takes him out of that process, he has done something — he being the Member — that is also part of the functioning of the legislative process, which is the test,” Manning said.

Attorney Richard Salzman, who is representing Hanson, called that argument “absolutely wrong” and said Hanson’s actual firing involved no legislative act and thus shouldn’t be considered under the clause.

Instead, Salzman argued, the court should look 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.

But the justices did press Salzman on the potential problems that could be created by allowing CAA cases to move forward. Justice David Souter expressed concern that if a Member was sued under the CAA for unlawful firing, he or she might have to choose between presenting a defense or keeping sensitive legislative matters private.

“I mean, what if he does not want to waive the privilege?” Souter added. “Is his only choice, in effect, to sit moot and lose the case?”

Salzman argued that such a situation would be rare, as most of the time such decisions would have little to do with sensitive matters.

“District courts will have to deal with the proffered evidence on a case-by-case basis,” Salzman said. “Obviously, the context matters with respect to any evidentiary privilege.”

Attorney Thomas Caballero also represented Hanson before the court, taking up the case on behalf of the Senate after Majority Leader Harry Reid (D-Nev.) and Minority Leader Mitch McConnell (R-Ky.) pushed through a resolution ordering a friend of the court brief to be filed.

Caballero argued that the point of the CAA is to ensure that legislative branch employees enjoy the same protections given to executive branch and private-sector workers.

“This court has made clear that the clause is robust, protects activities outside of just speech and debate on the floor of either [chamber], but that it shouldn’t be extended beyond what is necessary to preserve the independence of the legislative process,” Caballero said.

For her part, Manning argued that only 25 percent of the employees under the CAA work for Congressional offices and would be affected by the ruling. She also added that the Office of Compliance serves as a way for those employees to file complaints against their bosses.

After the hearing, she said the OOC offers the same benefits of going to federal court with certain added perks.

“The biggest advantage is that it’s expedited,” she said. “They’re out of there in 60 days.”

Hanson’s original lawsuit against Dayton was filed in 2003 in U.S. District Court. In an August 2006 decision, the U.S. Court of Appeals for the District of Columbia Circuit ruled that the case could move forward.

The court is likely to make a decision in the case by the time its current session ends in June.