Politicians come and go, but NYC district attorneys can be more or less forever: from 30-year men like former Manhattan DA Robert Morgenthau to current Queens DA Richard Brown, approaching three decades on the job himself.

That is one of the reasons that one of the more revelatory races during Tuesday’s primary day, on which Mayor Bill de Blasio won an expected blowout victory, was the down-ballot contest for Brooklyn’s top prosecutor.

It was a six-person primary field, including five candidates who had deep experience working in the Brooklyn office. All were looking to inherit the reformist mantle of Ken Thompson, the former district attorney who died in the middle of his term last year. Eric Gonzalez — who has been serving as acting district attorney — won the office outright on Tuesday, fending off challenges from the left with a message of “fairness and safety.”

With no Republican on the ballot in November, Gonzalez is poised to start a full term and begin what could be a long run in Brooklyn.

In a conversation on Thursday Gonzalez gave some hints at what New Yorkers can expect from his tenure.

Who is the presumptive DA?

Gonzalez was raised in Brooklyn and talks about giving people a sense of safety — a typical mindset for a DA. Yet he’s equally serious about the reforms he helped Thompson implement and says he’ll further them.

That balancing act is clear in his descriptions of the campaign trail, which he says was “eye-opening.” Appearing at events for his old job as chief of the trial division, he says he mostly heard complaints about public safety, drugs and quality-of-life violations. While stumping, he spoke to people who “felt that the criminal justice system had been too harsh.”

Yet he also said he picked up on a lack of attention to victims of certain crimes — people who might not get much support after their homes are broken into or they are assaulted. Those people may benefit from social workers, Gonzalez says.

He seems to track a similarly methodical path toward reform, pointing to a few granular issues he’d like to address.

Defense attorneys in New York perennially complain about prosecutors not being required to turn over evidence and materials early enough to allow for a substantive defense. This is known as “discovery,” and the New York State Bar Association has endorsed a plan to change the laws governing it in New York to even the playing field. (The problem was a factor in at least 10 recently overturned convictions in Brooklyn, Gonzalez says). Gonzalez says he’s a “supporter of open-file discovery,” which is the principle of both sides having access, though the devil will be in the details. He hasn’t taken a position on legislation but is “trying to create an electronic system” in Brooklyn to move materials as quickly as possible to defense attorneys, something he says would be new in NYC.

A spokesman from the Legal Aid Society, which supports discovery reform, calls this idea a “step in the right direction.”

Another area of reform has been marijuana policy: Gonzalez says he helped his predecessor write the much-lauded policy that tosses low-level weed possession cases under certain circumstances, such as if someone doesn’t have a warrant or criminal convictions.

The policy doesn’t apply to people caught smoking in public. It has had its critics because fewer people are prosecuted for having the drug on them, but those who are prosecuted are disproportionately black or Hispanic. Gonzalez says one way to address this may be to consider the nature of a warrant as opposed to just saying, open warrant, case continues.

The future of prosecution

These and other efforts will be worth watching, and criminal justice reformers are already saying they’re planning to keep an eye on Gonzalez. His decisions and conduct will have an effect on Brooklynites, but will also fit into a national conversation about criminal justice reform. Voters have turned out top prosecutors in places like Chicago for insufficient attention to reform and a lack of police accountability.

Gonzalez places himself among the newer wave of reformers: he is part of a group called “Fair and Just Prosecution,” made up of about 20 DAs who discuss reform efforts.

The group includes Manhattan District Attorney Cy Vance, as well as the new DA for Chicago’s Cook County, and other prosecutors from large cities.

Gonzalez says he was invited into the group because of his reform work under Thompson, work that also brought him overwhelming support from local and national politicians and crack campaign staff for his run. It all contributed to a decisive victory and an office entirely his own. Two days after victory, he said he intends the office to be among the “most progressive” in the country.