“The prosecutor has more control over life, liberty, and reputation than any other person in America. His discretion is tremendous. . . . While the prosecutor at his best is one of the most beneficent forces in our society, when he acts from malice or other base motives, he is one of the worst.” Those words from Robert Jackson come to mind as scandal engulfs the Fulton County, Georgia, D.A., Fani Willis, who allegedly hired her boyfriend to prosecute President Trump.

“The Real Housewives of Atlanta” has nothing on what’s happening in this case. The accusation, in a court filing by one of Mr. Trump’s co-defendants, Michael Roman, is that Ms. Willis hired as special prosecutor on the case a married man, Nathan Wade, who is also her boyfriend and has never prosecuted a felony. Mr. Wade has since been paid more than $650,000. Mr. Roman wants them both disqualified and the charges dismissed.

We don’t yet know how Ms. Willis will answer those charges. Her response is due to be filed next month, and a hearing will follow. Ms. Willis, like her defendants, is owed her day in court. Now is a moment, though, to mark that any allegation that a prosecutor put a finger on the scales of justice ought to trouble not only the defendants, but also every American. The rush to insist that Ms. Willis’s racketeering case can survive her possible peccadillos strikes us as dubious.      

At Big Bethel African Methodist Episcopal, Ms. Willis called herself a “very flawed, hardheaded and imperfect servant.” She suggested that her critics are animated by racism. She insisted that Mr. Wade’s credentials are “impeccable.” Mr. Roman sees a defective appointment and a pooling of the largesse that flowed from Mr. Wade’s hiring and funded a lavish lifestyle. A matter reserved for the bedroom, Mr. Roman contends, has made itself felt in the courtroom.

Even those inclined to align with Ms. Willis’ sprawling racketeering case against Mr. Trump and 18 others are expressing concern. In the Times, a law professor, Clark Cunningham, asserts that he “has generally approved of the way Ms. Willis has handled the case.” He believes that it “has a solid factual and legal foundation.” He calls it  “arguably the most important case in the nation, and potentially of historic significance.” 

Yet Mr. Cunningham allows that the “judicious and farsighted course would be for Ms. Willis to take a personal leave of absence and turn over” the case. The Washington Post reports that an ally of Ms. Willis, Norm Eisen, is urging Mr. Wade to step aside because “we mustn’t lose time on the calendar” in prosecuting Mr. Trump before the election. Attorney General Garland and Special Counsel Jack Smith are also fretting about the calendar.

The taproots of prosecutorial discretion are found in the constitutions of both America and Georgia and the assignment to “take care” that the laws be “faithfully executed.” The ordinances of Fulton County, we’ve already noted, mandate the avoidance of even the appearance of impartiality. Whether Mr. Wade was faithful in his marriage is a private concern. Whether Ms. Willis, an elected official, was faithful to the constitutions and laws is a public one.

Which brings us back to Robert Jackson. One of the points FDR’s attorney general, later a Supreme Court justice, made in his famous speech on prosecutors is the staggering amount of power they hold. In deciding what cases to take on, he argued, prosecutors may have enormous discretion. One slip, though, can lead to abuse — to indiscretion — and it’s not too soon to say that the judges overseeing Ms. Willis need to address that possibility.