“This bill would cheapen the meaning of lynching by defining it so broadly as to include a minor bruise of abrasion,” he said. “Our national history of racial terrorism demands more seriousness of us than that.”

Mr. Paul said that he took lynching seriously, but “this legislation does not.”

Ms. Harris rose to object, delivering a seething broadside against Mr. Paul as she noted that even as they debated, mourners were gathering to honor George Floyd, the African-American man who died last week after a Minneapolis police officer knelt on his neck for nearly nine minutes.

“The idea that we would not be taking the issue of lynching seriously is an insult — an insult to Senator Booker and Senator Tim Scott and myself,” she said from across the chamber floor, referring to the South Carolina Republican who helped write the bill and is the party’s lone black senator.