“THE PROSECUTOR has more control over life, liberty and reputation than any other person in America. His discretion is tremendous.” Those words from then-Attorney General (and later Supreme Court Justice) Robert Jackson nearly 80 years ago underscore the importance of the choices Northern Virginia voters will make in the upcoming contests for commonwealth attorneys.

Four jurisdictions will change leadership in the prosecutor’s office as a result of longtime incumbents leaving or being voted out. In Arlington-Falls Church, Parisa Dehghani-Tafti, a former public defender who heads an innocence project organization, is running unopposed in the Nov. 5 general election after defeating incumbent Theo Stamos in the Democratic primary. In three other Northern Virginia jurisdictions, spirited contests are being waged against the backdrop of a national debate over criminal-justice reform.

In Fairfax, we endorse Steve Descano (D), a West Point graduate, Army veteran and former federal prosecutor, over Jonathan Fahey, an independent who has been endorsed by the Republican Party. Mr. Descano was not our choice in the Democratic primary in which he beat incumbent Raymond F. Morrogh, but in his matchup against Mr. Fahey, a former federal prosecutor who once worked in the commonwealth’s attorney’s office in Fairfax, Mr. Descano has the better, more forward-looking agenda.

Mr. Descano favors moving past “tough on crime” policies such as aggressive drug interdiction and capital punishment to an approach that makes informed distinctions about who poses a threat to public safety. Mr. Fahey, by contrast, seems satisfied with the status quo and has criticized Mr. Descano as lacking relevant experience. Mr. Descano’s six years as a federal prosecutor, mainly in the criminal tax division and consumer protection branch, is limited, but his military service and work in the community — notably helping to launch the Fairfax County Police Civilian Review Panel — show his leadership skills. No doubt he would face challenges in taking over an office that is fiercely loyal to Mr. Morrogh (who has endorsed Mr. Fahey) but Mr. Descano is well prepared for the job.

In Prince William County, Paul B. Ebert is retiring after 50 years as commonwealth attorney. We believe Amy Ashworth, whom we endorsed in the Democratic primary, is best suited to bring needed changes to the office. While her Republican opponent Mike May, a former member of the Board of County Supervisors, usefully identified problems in the office in his run four years ago, Ms. Ashworth is better poised to undertake reform. Her 23 years as a practicing lawyer in Prince William, both as a prosecutor and defense attorney, give her perspective on the challenges facing the county. Among her priorities are tackling domestic violence, diversifying the office and looking at new strategies to keep juvenile offenders from reoffending.

Loudoun County Commonwealth’s Attorney Jim Plowman is leaving the office he has held since 2003 to go on the bench. Vying to replace him are his chief deputy, Nicole Wittmann (R), and veteran local attorney Buta Biberaj (D), whom we endorse.

Ms. Wittmann is a skilled prosecutor, but the office — and the citizens it serves — would benefit from a fresh approach that reflects concerns about overcriminalization, overincarceration and racial disparities. Ms. Biberaj, who has practiced law in Loudoun for more than 25 years and served as a substitute judge in the county courthouse, knows the county well. Her robust agenda includes ending cash bail, providing more supports for victims and tackling the school-to-prison pipeline through partnerships with schools, community officials and business leaders.

These are critical elections. The deadline to register to vote is Oct 15.

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