“I blame Larry Nassar,” the Olympic gold medalist Simone Biles told assembled senators on Sept. 15, “but I also blame an entire system that enabled and perpetrated his abuse.”

Ms. Biles was one of four gymnastics champions who gave searing testimony about the F.B.I.’s gross mishandling of the investigation of Larry Nassar, a former gymnastics team doctor convicted on multiple counts of sexually abusing young women in his charge. A U.S. Department of Justice review, published by the Office of the Inspector General this July, found that F.B.I. agents delayed commencing an investigation, neglected to interview key witnesses and failed to notify state law enforcement officials. The F.B.I.’s inaction, the report noted, left Mr. Nassar free to continue working with girls and young women and thus to assault at least 70 athletes who might have been spared if federal agents had done their jobs.

Speaking before the Senate…