Nancy Mace (R-S.C.) is facing a defamation lawsuit filed by one of the four men she has publicly accused of sexual abuse in a floor speech, in a case that could test the legal protections members of Congress have for their official conduct.

One of the men Rep. Nancy Mace (R-SC) accused of sexual abuse in a fiery speech on the House floor last month is suing the congresswoman for defamation, a test of legal rules that members of Congress say protect remarks in the chamber.