Norma Holloway Johnson’s career began in the newly integrated Justice Department of the early 1960s and has culminated in a prized seat on the federal bench. But Johnson — who presided over the grand jury investigation that spurred the impeachment of a president — may be best remembered for how she conducts herself in the next few weeks.

Johnson is at the center of a fast-moving controversy that threatens to engulf the federal trial court in Washington, D.C. A special panel of her peers has been chosen to investigate whether Johnson, as chief judge of the court, improperly shuttled the criminal prosecutions of well-connected Democrats to judges appointed by President Bill Clinton.