Suffolk County District Attorney Dan Conley’s announcement that he will not seek office next year has changed the calculus in what is shaping up to be a busy state election year.

Conley’s decision to end his 16-year tenure in office immediately sparked a scramble for the seat. At-large City Councilor and former assistant district attorney Michael Flaherty is mulling a run for the office as is City of Boston Corporation Counsel and former state Rep. Eugene O’Flaherty. State Rep. Evandro Carvalho, who had waded into the special election for the 1st Suffolk Senate District seat formerly held by Linda Dorcena Forry, withdrew from that race to formally announce for the Suffolk County district attorney seat Monday.

Carvalho and former defense attorney Shannon McAuliffe, who served as director of the Boston office of the youth antiviolence group Roca, are so far the only two officially in the district attorney race.

McAuliffe, who had planned to take on Conley before he announced he would not seek re-election, is running on a reform platform and is against mandatory minimum sentences and the cash bail system that criminal justice reform advocates say unfairly target low-income defendants. McAuliffe also supports raising the age at which defendants can be charged as adults from 18 to 19.

Also said to be mulling a run is Rachael Rollins, a former federal and state prosecutor, chief legal counsel for MassPort and former president of the Massachusetts Black Lawyers Association.

Carvalho, in a press release sent to news media on Monday, noted that he has co-sponsored and advocated on behalf of criminal justice reform measures supported by the Massachusetts Legislative Black and Latino Caucus, the Progressive Caucus and other reform-minded legislators, including repeal of mandatory minimums for non-violent drug offenders, raising the age of criminal responsibility and the expungement of juvenile records.

“We need a District Attorney who understands the difference between a young man who needs a second chance and a violent criminal who needs to go to prison,” Carvalho said in his press statement. “We need a district attorney who is from this community with a record of service to the community. I will be that district attorney.”

The contested race for the Suffolk County seat comes in the midst of the ACLU of Massachusetts’ “What a Difference a DA makes” campaign to spark voters’ interest in the often-unnoticed races for district attorneys by highlighting the offices’ role in criminal justice policy. Rahsaan Hall, who directs the organization’s Racial Justice Program, said the Suffolk County race is particularly important.

“The Suffolk County district attorney’s office is the most powerful DA’s office in the commonwealth,” he said. “It has the greatest number of people of color under its jurisdiction and is a high-profile position.”

Hall said much of the state’s racial disparities in sentencing originate in Suffolk County, where large numbers of people of color have been locked up for non-violent drug offenses.

“The Suffolk County district attorney has a tremendous role to play in reducing those disparities,” he said.

District attorneys, including Conley, have weighed in on criminal justice reform debates, with most opposing measures like the elimination of mandatory minimums for nonviolent offenders and the decriminalization and legalization of marijuana.

Hall said voters should also pay attention to candidates’ positions on forfeiture laws, through which district attorneys can seize property from defendants charged with drug crimes.

“Police can grab money even if a person hasn’t been convicted,” he noted.

District attorneys split the funds with police departments. Hall and other criminal justice reform advocates say funds seized in drug cases should be spent on drug treatment and prevention, rather than at the discretion of police and district attorneys.