Brooklyn D.A. candidate Marc Fliedner performs Bruce Springsteen’s “American Skin (41 Shots)” at the Starr Bar. Dylan Hansen-Fliedner/Marc Fliedner for DA

On a Friday night, Marc Fliedner takes the stage at a Democratic Socialists of America (DSA) fundraiser show at Starr Bar in Bushwick. As his backing band tunes its instruments, he tells the young, mostly white crowd why they should elect him as Brooklyn district attorney. Then he sings Bruce Springsteen’s “American Skin (41 Shots),” written about the 1999 police killing of Amadou Diallo, and exhorts the crowd to vote in the September 12 primary — “Marc for D.A.!” he yells. “Marc for humanity! Marc for DSA! Marc for justice!”

The Democratic primary for district attorney of Brooklyn has seen six candidates vie to take up the mantle of the late Kenneth Thompson, the celebrated district attorney who died last October. This crowded field of progressives — all the candidates support some kind of bail reform, discovery reform, and an end to “broken windows” policing — is likely to make it difficult for any single challenger to match the entrenched support of the incumbent, acting D.A. Eric Gonzalez, who served as second-in-command under Thompson.

But Fliedner has emerged as an outlier of sorts in recent media coverage and in the polls. Among a group of challengers who’ve been described as “insurgent,” he’s the only one who’s tapped into the network of engaged progressive voters galvanized by Bernie Sanders’s 2016 campaign. Steve Panovich, Fliedner’s chief strategist, says he was a high-level Bernie operative, and the backing band at Starr Bar was made up of people he knew through the campaign. Fliedner has been endorsed by Sanders’s Our Revolution organization; he proudly touts his membership in the Democratic Socialists of America organization and wore his DSA rose pin at a recent candidate forum.

A small-sample poll released on August 25 pegged 42 percent of polled Democrats as still undecided about the race, which Fliedner sees as evidence that Gonzalez has failed to reach Brooklyn voters despite having blanketed the borough with ads. (The incumbent has raised twice as much as all his challengers combined.) Fliedner came in with 10 percent support to Gonzalez’s 19 percent, but since then his campaign has received a bump from Our Revolution phone bankers, and it’s hosting a concert with musicians and comedians this week at Brooklyn Bazaar; the space was given to them for free by a Bernie supporter.

Fliedner isn’t afraid of being contrarian — in fact, he’s cultivated a crusading “outsider” stance in the race, despite having spent almost thirty years as an assistant district attorney in Brooklyn. One of his most significant heresies is a refusal to participate in the deification of Thompson, who has been lauded at recent forums by candidates eager to claim his legacy. Fliedner left Thompson’s office after a dispute over the trial of Peter Liang, the police officer who fatally shot Akai Gurley in 2014. Fliedner prosecuted Liang and secured an unprecedented conviction on a manslaughter charge (he says this charge was already a compromise), but office leadership decided to treat Liang as an “extraordinary” case and give him probation instead of jail time. Gonzalez, who has received donations from bail bond companies and was endorsed by a police union, declined a Voice request for comment.

Fliedner, who says he had already been frustrated by what he saw as ineffectiveness and mismanagement in the D.A.’s office, quit to start a private civil rights firm, deeming the system broken beyond repair. After his departure he also described Thompson to the media as an “abusive” boss who “misuses his staff”; he now admits that he had no idea Thompson had been diagnosed with cancer, but stands by the characterization. He also praises Thompson’s predecessor, Charles Hynes, whose tenure was clouded by a number of corruption scandals but whom Fliedner says sought to create constructive alternatives to incarceration. Fliedner wants to go even further, though: Other candidates might be progressive, he says, but they’re not coming from the “front-row, impassioned place” he is. He vows not just to overturn the culture of the D.A.’s office to align with his reformer’s “vision” but to enact “legitimate systemic change in policy.”

Fliedner and Panovich, who took over the campaign in March after Fliedner fired consultants from the pro-LGBTQ Victory Fund (Fliedner is the first out gay man to campaign for D.A. anywhere in the United States), say they’re hoping to appeal to a small group of “engaged” progressive voters in order to beat Gonzalez’s “machine” campaign. It’s not exactly clear who they think counts as an “engaged” voter, but Fliedner praised the crowd at Starr Bar to me repeatedly, calling them “the folks that get it” and saying DSA “perfectly defines him” against those who “purport to be progressive.” He sees his campaign, he says, as an attempt to see “whether the post-November motivations of millennials turns into a vote for a D.A. candidate.”

When Fliedner first came onstage, this crowd seemed unenthused about the prospect of being preached to by a candidate for district attorney. Once he ramped up his rhetoric at the end, they responded with scattered cheers and applause, but it wasn’t clear afterward that he had won all their votes or even convinced them all to vote.

Fliedner would be the first to admit that, even though they may be one of his target demographics, mostly white millennial socialists aren’t the Brooklyn demographic that would be most affected by reform in the D.A.’s office. He’s joined other candidates in deploring the damage that overpolicing and mass incarceration have inflicted on Brooklyn’s communities of color. But Panovich admits there have been some “hurdles” in canvassing in the black communities, even though Fliedner says those are the places where his work as a prosecutor gave him the most connections. (He lives in Bay Ridge but says he hasn’t spent much time campaigning there.)

Marc Fliedner at the Brooklyn J’Ouvert parade, in a ceremonial costume designed by Roy Pierre Dylan Hansen-Fliedner/Marc Fliedner for DA

Fliedner does acknowledge that there’s been some distance when he’s campaigned in black neighborhoods. He says his campaign manager, Kaz Mitchell, who is black, is often met with skepticism when she canvasses for “the white guy,” and says that he hasn’t been invited to certain events in black churches because he’s LGBTQ. “I will ask for five minutes, though,” he says, “and you’d be amazed what can happen in those five minutes.” Once voters become familiar with his strong record of prosecuting cops (Liang was not the first), he argues, “they hear me.”

Still, positioning himself as the best D.A. candidate for people of color has at times generated tension with the other candidates. At a forum in Bed-Stuy on August 29, Fliedner declared he was the only candidate in the race who had said “Black Lives Matter.” The comment provoked a fierce response from Ama Dwimoh, one of two black women candidates in the race, who was sitting next to Fliedner at the time. She said she’d lived the issues at stake in the race in a way Fliedner never had and asked him “how dare he” question her commitment to improving the lives of black people.

Speaking over coffee last Saturday after spending the morning campaigning at Smorgasburg in Williamsburg, Fliedner said he “respected [Dwimoh’s] journey” but pointed to what he saw as shortcomings in her platform — she advocates for mandatory jail sentences, he said, which is exactly the kind of thing that has resulted in racial inequity in the criminal justice system. During the forum, Dwimoh and Patricia Gatling, the race’s other black candidate, sounded just as progressive as Fliedner, if not more progressive on “broken windows” and alternatives to incarceration; both saw low numbers in the August 25 poll, though, which City Limits speculated could mean the candidates are splitting the black vote.

Two days later, Fliedner and Panovich, dressed in ceremonial costumes designed by the Trinidadian artist Roy Pierre, marched with Pierre’s posse in Brooklyn’s annual J’Ouvert celebration. As the sun rose, Fliedner bopped along to Caribbean music, flanked by thousands of black Brooklynites and an unprecedented number of police vans, and looking only slightly uncomfortable. Later, he changed out of his costume and campaigned at the West Indian Day Parade on Eastern Parkway.

Fliedner is quick to highlight the similarities between his candidacy and that of Larry Krasner, the progressive civil rights lawyer who won the primary for district attorney of Philadelphia earlier this year. Krasner, who got 38 percent of the vote in a primary of seven candidates, was also endorsed by Our Revolution and hailed as a progressive. But he was also able to earn coverage as the “Black Lives Matter candidate” in a way Fliedner hasn’t — perhaps because Krasner defended BLM activists and sued the police 75 times, or perhaps because all the challengers in Brooklyn share Fliedner’s rhetoric about ending mass incarceration.

“New York politics is extremely identitarian,” Panovich told me, almost by way of dismissal. A Fliedner victory would likely be hailed as a progressive high-water mark on the order of Krasner’s, but the much-discussed wave of progressivism that has buoyed candidates across the country hasn’t translated his message — he’s arguably the most radical candidate, and Mr. Gonzalez’s most vocal critic — into a broad base of support. Branding himself as “the true progressive in the race,” in other words, has led him to place his hopes in a group of very political, very mobilized Brooklynites who also happen to be the least affected by the system he wants to reform.

Fliedner is nothing if not passionate about those reforms, but if he ever gets the chance to make them, it’ll be thanks to a much narrower coalition than Krasner had. As the primary nears, a campaign that he’s quick to describe as “unconventional” seems to be attempting to straddle two different Brooklyns. Its impact, though, has been more substantial in the “new” Brooklyn, the gentrified borough of Williamsburg and Bushwick. Whether that will be a winning strategy is unclear. As Fliedner himself said, emphasizing the strength of his convictions: “If you try to please everyone, you end up hurting some.”