A test is shaping up for one of the Constitution’s most adamant provisions, the Speech or Debate Clause, now that Representative Nancy Mace is being sued for a speech she delivered on the House floor. In February, Ms. Mace herself characterized her tirade as a “scorched earth” speech. She accused four men in her district, including her ex-fiancé, of “some of the most heinous crimes against women imaginable.” One of them is now suing her for defamation.

The individuals named by the South Carolina congresswoman for what the Hill calls “allegations of sexual abuse and voyeurism” deny any wrongdoing. The man suing Ms. Mace, Brian Musgrave, says that he is filing for defamation “to recover that which has been wrongfully taken from him — his good name and reputation.” Ms. Mace’s speech prompted him to declare: “‘I am not a rapist.’ ‘I am not a predator.’ ‘I am not a sex trafficker,’” the lawsuit says.