Ketanji Brown Jackson (U.S. Sentencing Commission)

President Barack Obama made his sixth nomination to the District’s federal trial court Thursday, tapping U.S. Sentencing Commission member Ketanji Brown Jackson.

The nomination is notable because, if confirmed, Jackson would become only the second African American woman to serve as a full judge on the U.S. District Court for the District of Columbia, and would be the first to be robed in more than 30 years.

It’s a stunning demographic deficiency in a city where a quarter of the population — more than 150,000 — are black women. Currently none of the district’s 15 active judges and six senior judges are black women. (Four are black men, and eight are white women.)

The first and only African American Article III judge on the court was Norma Holloway Johnson, who was nominated by President Jimmy Carter and confirmed in 1980. She served until 2003 and died last September.

One of the district’s three term-appointed magistrate judges, Deborah A. Robinson, is a black woman. The federal appeals court here also has two black female judges, Judith W. Rogers and Janice Rogers Brown.

Obama has previously nominated two white women (Beryl A. Howell and Amy Berman Jackson), a black man (Robert L. Wilkins), a white man (James E. Boasberg) and a Hispanic man (Rudolph Contreras). All have been confirmed and robed.

UPDATE, 1:15 P.M.: Note that, in 1999, President Bill Clinton nominated a second black woman to the D.C. bench — Rhonda C. Fields, a veteran prosecutor with the District’s U.S. attorney’s office — but she was not confirmed before Clinton left office. Should Obama not win re-election in November, Jackson’s nomination could see the same fate.