And they are drawing on personal experience for lessons on how to be tough on crime without being needlessly harsh.
Ms. Ayala, in Florida, said her husband had once been caught up in the juvenile justice system, and later served seven years in prison on drug charges. He now works for a nonprofit. “You have to distinguish between a child who is misguided and frustrated from home issues, and a child who is dangerous,” she said.
The thin ranks of black elected prosecutors do include some high-profile figures. Since the Ferguson protests, R. Seth Williams, the Philadelphia district attorney, has held informal talks with a small group of African-American peers on the best ways to respond to police killings. And it was Marilyn Mosby, the state’s attorney for Baltimore, who led the investigation into the case of Freddie Gray, a 25-year-old black man who died after riding unsecured in a police transport wagon.
Six officers were charged with crimes; the first trial ended in a hung jury, and three officers were acquitted. Ms. Mosby dropped the remaining charges.
But she is unapologetic. Had the case been handled differently, “there would have been no accountability,” she said in an interview. “You have to have a seat at the table, and you have to be the change you want to see.”
A small group of advocates are leading the charge. The National Bar Association has urged black line prosecutors to run for office; the National Black Prosecutors Association is offering to mentor candidates; and Mr. Soros, through Color of Change and his growing network of Safety and Justice PACs, has funneled nearly $5 million into the cause since last year.
Outside Atlanta, Mr. Soros spent $147,000 helping a DeKalb County line prosecutor, Darius Pattillo, seek the district attorney’s post in neighboring Henry County; his general-election opponent recently quit the race.
Not all the campaigns have ended so well for Mr. Soros: Robert Shuler Smith, a black district attorney whom he helped win re-election in Hinds County, Miss., has since been indicted on charges of conspiring to aid a criminal defendant.
And in Houston, Mr. Soros’s first choice, Morris Overstreet — a former judge who was the first African-American elected to a statewide office in Texas since Reconstruction — was defeated in the Democratic primary by a white woman, Kim Ogg. Mr. Soros has now spent $500,000 to aid her against the Republican incumbent, Devon Anderson.
Mr. Soros, who declined to be interviewed, has also supported Hispanics seeking prosecutors’ posts in Arizona and New Mexico, a spokesman said.
“Race does not explicitly play a role, but in seeking candidates who understand the injustices of the current system, many of them turn out to be African-American or Latino, because it is people of color who have been disproportionately affected by those injustices,” the spokesman, Michael Vachon, said in an email.
Mr. Crump said he wants to focus attention next on elected prosecutors in Staten Island, Minneapolis, and Baton Rouge, places that have each seen high-profile killings of black men.
But first, Brooklyn voters next year will elect a successor to Ken Thompson, the borough’s first black district attorney, who died of cancer last month before finishing his first term.
In what was apparently his last interview, Mr. Thompson made clear that electing black prosecutors would not just mean charging police officers who might not have been charged before, or declining to seek prison time for blacks who might have been dealt with more harshly in the past.
He pointed to his decisions to stop prosecuting most low-level marijuana cases, create a program aimed at helping people clear warrants for low-level offenses, and devote resources to reversing wrongful convictions. Electing more black district attorneys, he said, might give blacks and the poor a fairer shake.
“We should first determine if those who enter the criminal justice system belong in the criminal justice system — not just sort of process them on,” he said.
“There are a lot of lock-’em-up, keep-’em-moving D.A.s,” he added. “I’m not one of those guys.”