A recent wave of court activity on several employment-discrimination cases brought by former staffers may be setting up a split between federal appeals courts over whether Members may successfully claim constitutional immunity from suits brought under the Congressional Accountability Act.

Last week, a federal district judge denied a motion by Sen. Mark Dayton (D-Minn.) to dismiss a case brought against his office by former staffer Brad Hanson, who claimed Dayton fired him after he told the Senator he had a heart condition. Without written explanation, U.S. District Judge Richard Leon ruled that Hanson’s case could proceed to trial.

There is no word yet on whether Dayton’s attorneys in the Senate Employment Counsel’s office would file an immediate appeal in U.S. Court of Appeals for the District of Columbia Circuit.

“We’re still reviewing the matter,” said Chris Lisi, Dayton’s communications director, adding, “The case has no merit.”

If Dayton files an appeal of Leon’s motion it would mark the second appeal in recent weeks of a district judge’s decision to deny a Member’s motion to dismiss a CAA case on Speech or Debate Clause grounds.

In late August, another D.C. district judge ruled that the Constitution doesn’t automatically afford lawmakers immunity from employment discrimination suits brought by senior legislative aides — an apparent first since the 1995 law allowed staffers to bring their grievances to court.

In that case, U.S. District Judge James Robertson denied a motion by Rep. Eddie Bernice Johnson (D-Texas) to dismiss a discrimination and wrongful-termination suit brought by her former chief of staff, Beverly Fields. Johnson’s attorneys filed an immediate appeal with the D.C. Circuit and are now awaiting a decision on whether the appellate court will agree to hear it.

Although the Fields case was not the first CAA case to be allowed to proceed — a lawsuit brought by a former Ways and Means Committee staffer was dismissed on its merits earlier this year after Chairman Bill Thomas (R-Calif.) refused to employ a similar constitutional defense — the Fields decision was groundbreaking because it marked the first time a judge ruled against a Member who cited the Speech or Debate Clause of the Constitution as a defense in such a case.

Hanson’s suit against Dayton marks only the second time a district court judge has allowed a discrimination case brought by a legislative staffer to proceed. Hanson’s attorney, Richard Salzman, said he was pleased with the decision.

Three Senators and Johnson have invoked the clause in Article I that protects Members from being questioned about “Speech or Debate in either House … in any other place” as a defense against suits brought under the CAA, the landmark 1995 law that applied 11 federal labor and workplace laws to the legislative branch.

In 2002, a Colorado district court ruled that Rita Bastien, a former state director for Sen. Ben Nighthorse Campbell (R-Colo.) was sufficiently tied to the legislative process to trigger the immunity. Bastien appealed to the 10th Circuit, which agreed to hear her case. A three-judge panel heard oral arguments in March and could rule anytime on whether her age-discrimination suit was correctly dismissed by the lower court.

If the appeals court for the D.C. Circuit agrees to hear either Johnson’s case or a potential Dayton appeal and decides differently than the three-judge panel for the 10th Circuit, the two appellate courts would then be split — increasing the likelihood that the Supreme Court could take up the issue. In the Bastien case, at least, both sides have expressed a willingness to take their appeals to the high court.

If Speech or Debate immunity is determined by either the Supreme Court or individual circuits to prohibit Congressional staffers from suing their employers for discrimination or other wrongdoing, only custodial workers, cafeteria employees and the Capitol Police would likely be covered by Congress’ 1995 promise to follow the same workplace laws as the rest of the country and to submit to adjudication in federal court when an employee believes one of those laws has been broken.