If there is one mistake that will likely haunt Rep. Eliot Engel (D-N.Y.) for years to come, it was when a live TV broadcast captured him begging to speak at a June news conference about vandalism in the Bronx. 

The problem wasn’t that he wanted to speak. It was why he wanted to: “If I didn’t have a primary, I wouldn’t care,” he said. 

The moment was pivotal in the race, in large part because Engel’s challenger, Bronx middle school principal Jamaal Bowman, had the infrastructure in place to take advantage of it. 

Within 24 hours, Bowman’s campaign tapped into its deep Rolodex and email list for more than $107,000, making it the best fundraising day of the campaign.

Meanwhile, an independent expenditure operation erected by the Working Families Party and Justice Democrats, the left-wing group that recruited Bowman, blanketed the airwaves with 30-second TV spots casting the remarks as evidence of Engel’s indifference to the concerns of New York’s 16th Congressional District. The groups had already decided to hit Engel over the related issue of his absence from the New York City district during the height of the pandemic based on polling that showed it ranked as a higher concern among voters than the 16-term incumbent’s hawkish foreign policy record or ties to Wall Street and other corporate donors.

Those investments bore fruit on June 23 when Bowman took a 25-percentage-point lead over Engel in the in-person vote. Given the extremely low chance that Engel’s performance among absentee voters is strong enough to close that gap, Bowman ― and the activist left rooting for him ― declared victory. Local authorities will begin counting absentee ballots later this week.

The all-but-official victory is a testament not just to the salience of Bowman’s progressive platform and the hunger for new representation in a majority-minority district, but also the maturation of a progressive insurgency that boasted a fraction of the sophistication and resources just two years ago.  

Despite an electoral record that is mixed at best, the left wing of the Democratic Party has been busy learning from its mistakes and building professional tools capable of matching the establishment’s might.

“We’ve been intentional about building infrastructure and an ecosystem that can take on decades worth of the establishment’s,” said Alexandra Rojas, executive director of Justice Democrats. “As progressives, if we’re not investing in media apparatus, polling apparatus, our ability to do research, in addition to the incredible field work that prioritizes talking to voters, then we’re not going to be able to mount serious challenges.”

Sens. Elizabeth Warren (Mass.) and Bernie Sanders (Vt.), who had been the left’s preferred candidates for the Democratic presidential nomination, shared a disdain for the traditional campaign playbook. Warren never hired a pollster to test which messages resonated most with voters, a decision many veteran strategists regard as disastrous. Sanders agreed to fund consistent internal polling this cycle only after a senior adviser threatened to quit if he would not do so. He declined to seek the endorsements of many politicians and refused to adjust his messaging when he emerged as a front-runner.

Many left-wing candidates and elected officials are instinctively suspicious of the kind of scientific campaigning that more moderate Democrats have used to run elections for decades. Figures like Sanders have thrived by defying conventional wisdom about what is necessary to win, so they question even the more innocuous elements of traditional campaigning. 

“We need to reject corporate candidates,” said Monica Klein, a progressive communications consultant whose clients include the New York Working Families Party, which endorsed Bowman in February. “But too often, progressives are also throwing tried-and-tested campaign tools out the window: polling, focus groups, message testing, normal relationships with the media.”

From the start, Bowman and the groups working with him were determined not to make that mistake. 

Ahead of the 2020 election cycle, Justice Democrats collaborated with the polling firm and think tank Data for Progress to help craft a system for ranking Democratic House seats based on their ripeness for a primary challenge.

Incumbent Democrats were given a numerical score reflecting the relative conservatism of their voting record and views, their seniority among House Democrats, their membership in centrist caucuses, the youthfulness and racial diversity of their district, the number of competitive elections they had survived and the typical turnout in their elections. For example, the two groups gave higher scores to white people representing majority-minority districts but also for seats with lower turnout, which tends to mean it would take less money to amass a winning number of votes. 

Engel, an older white man representing a majority-minority district and a member of the business-friendly New Democrat Coalition, fit several of the criteria. Despite a domestic policy record that had been trending leftward in recent years ― he is a co-sponsor of “Medicare for All” legislation and the Green New Deal resolution ― as House Foreign Affairs Committee chairman, he was best known for his hawkish foreign policy views. And in a district with about 251,000 active registered Democrats, 11% of those eligible voters cast ballots in Engel’s 2018 primary.

In New York, unlike states with “open” partisan primaries, only registered Democrats can cast votes in Democratic primaries, making the pathway that much more accessible for a newcomer hoping to amass more votes than Engel.

“Engel struck us as particularly viable [for a primary challenge] because of the primary system in New York being a first-round, winner-take-all, closed primary,” said Sean McElwee, a co-founder of Data for Progress. 

Other districts had a similar demographic profile but lacked a challenger of Bowman’s quality.

Billy Easton, then-executive director of the Alliance for Quality Education, a New York group that advocates for greater and more equitable state funding for public schools, nominated Bowman to run for the seat as part of a thorough recruitment selection process administered by Justice Democrats. Bowman, a teacher turned principal who founded the public middle school Cornerstone Academy for Social Action (CASA), had been active with AQE, rallying with parents to demand more money for education. 

Justice Democrats was impressed with Bowman’s charisma and the sincerity of his progressive convictions. They also saw the advantage of a figure with a natural base of support in the northeast Bronx, where CASA is located. 

“Our whole case was that Jamaal could build a coalition similar to the Obama coalition: young people, people of color and older white liberals tired of a 31-year incumbent,” said Waleed Shahid, communications director for Justice Democrats. 

Justice Democrats was founded by alumni of Sanders’ 2016 presidential bid, including Rojas, who were interested in taking the “political revolution” that Sanders had initiated to the halls of Congress. Initially starved for cash and media attention, they struck gold in June 2018 when Alexandria Ocasio-Cortez, a candidate they had recruited, unseated then-House Democratic Caucus Chairman Joe Crowley of New York.

But replicating the winning formula would take some trial and error. For one thing, Justice Democrats concluded that it was no longer worthwhile to endorse 70 candidates, as it had during the 2018 cycle. It instead announced that it would be focusing on recruiting primary challengers for a handful of safe House Democratic seats where they could not be accused of jeopardizing the party’s prospects in the general election.

The goal was to elect more members like Ocasio-Cortez and the rest of her “Squad” ― Rashida Tlaib (Mich.), Ilhan Omar (Minn.) and Ayanna Pressley (Mass.) ― in the hopes of eventually creating a cohesive bloc of progressive lawmakers capable of dictating policy within the House Democratic Caucus. (With more than 95 members of varying ideologies, the Congressional Progressive Caucus is rarely equipped to play that role.)

“There are some good people who want to push for stuff, but they don’t have the backup right now to do anything big,” Saikat Chakrabarti, a founder of Justice Democrats and then-chief of staff to Ocasio-Cortez, said in a November 2018 call with activists. “So we need new leaders, period. We’ve got to primary folks.” 

Justice Democrats would no longer have the element of surprise that it enjoyed during Ocasio-Cortez’s run, when Crowley and his allies underestimated its strength.

But it had new advantages at its disposal. In the intervening years, a network of left-wing campaign vendors has cropped up to serve the nascent sector of progressive candidates. That boomlet ironically accelerated when the Democratic Congressional Campaign Committee (DCCC), the House Democrats’ campaign arm, announced in March 2019 that it was blacklisting any consultants who worked for candidates challenging incumbent House Democrats. 

The move forced many already progressive consultancies to pick sides, prompting them to specialize in progressive campaigns. It was a new space with fewer of the old players and, for the firms willing to risk banishment from the establishment, more room to experiment. And progressive candidates looking for consultants willing to work for them needed only to look on DCCCBlacklist.com, a website Justice Democrats erected just for the purpose.

“The DCCC inadvertently created an ecosystem that ended up fostering a lot of innovation,” McElwee said

Many of the firms are run by veterans of the 2016 Sanders campaign or other left-wing races that have taken place since then. Connor Farrell, the former finance director for Dr. Abdul El-Sayed’s unsuccessful 2018 bid for governor of Michigan, founded the fundraising firm Left Rising, which ran Bowman’s fundraising. In 2019, Rebecca Katz, a former adviser to then-Senate Democratic Leader Harry Reid (D-Nev.) and New York gubernatorial challenger Cynthia Nixon, founded New Deal Strategies, which would handle Bowman’s press and communications in conjunction with Shahid.

Data for Progress, Bowman’s pollster, began conducting its own polling in January. And Luke Hayes, who became Bowman’s campaign manager in December, previously ran Tiffany Cabán’s nearly victorious run for Queens district attorney and New York state Sen. Alessandra Biaggi’s successful bid to unseat the former head of the GOP-aligned Independent Democratic Conference.

For months, Bowman’s campaign relied on a system of volunteer-heavy canvassing that progressive campaigns often think of as their secret weapon against establishment Democrats with other advantages. Bowman began using data accumulated during his field work to identify what would become his core voters ― the “Obama coalition” of young progressives, people of color and older white liberals.  

All the while, Bowman raised money at a steady clip. Thanks to Justice Democrats’ growth and the increased interest in progressive candidates, he hauled in more money in his first week on the campaign trail ― $71,000 ― than Ocasio-Cortez had in the first six months of her bid. 

Bowman also began picking up critical endorsements, including from the New York Working Families Party, a pillar of progressive politics in the state that had spawned its own ecosystem of campaign professionals and loyal elected officials over the course of two decades. (Ava Benezra, Justice Democrats’ campaigns director, had cut her teeth running WFP’s 2018 legislative primaries, which successfully ousted six former members of the GOP-aligned Independent Democratic Conference in New York’s state Senate.) 

The WFP’s influence was apparent early on: New York City Public Advocate Jumaane Williams, a longtime WFP ally and the highest-ranking Black elected official in New York City, joined the group at its endorsement news conference in February, lending Bowman critical mainstream legitimacy. The group would later advise the New York State Nurses Association, a labor union and member group of the WFP, on how to manage its endorsement of Bowman ― a deviation from the establishment to which the union was unaccustomed. 

The institutional left was also united in Bowman’s race, thanks in part to WFP’s role as a coalition builder. Andom Gebreghiorgis, Bowman’s prime progressive competitor, withdrew from the race in early June following conversations with Sochie Nnaemeka, the New York WFP’s state director. It was a contrast to what happened nearby in the 15th Congressional District, where divisions spawned an 11-person free-for-all primary that risked clearing a path for an anti-gay New York City councilman.

“This campaign was a real model of how different organizations with different strengths can work together in pursuit of a common goal,” Nnaemeka told HuffPost.

Still, the campaign had to adapt to a number of challenges, including local and national media outlets’ reluctance to take Bowman’s bid seriously. New Deal Strategies, which had four people working on Bowman’s campaign, worked hard to cultivate a relationship with the Riverdale Press, an in-district newspaper with 10,000 paper subscribers. Bowman also had success publishing op-eds, writing in Chalkbeat in January about ways to address the trauma experienced by impoverished students, and on NBC News in March about how he had felt the effect of heavy-handed policing practices, including New York City’s notorious stop-and-frisk policy. 

“Almost everyone who wrote about Jamaal said ‘no’ first,” Katz recalled.

Then came the COVID-19 pandemic, which initially seemed like it would deprive Bowman’s campaign of a key asset by prohibiting in-person canvassing. 

But it ended up providing him the chance to show his support for the people of the district and bring Engel’s weakness into sharper relief. Bowman’s team pivoted to phone-banking, ultimately making an estimated 1 million calls; 850,000 of them were conducted by volunteers associated with the Sunrise Movement, the youth-led climate action group. He held regular video discussions of policy with activists that he posted on Facebook, as well as tutorials for parents seeking tips about in-home education during the quarantine.

And Bowman began joining the protests of nurses at local hospitals who were angry at the shortage of personal protective equipment. His participation in those demonstrations helped him win the support of NYSNA, the nurses union that endorsed him in late May.

New York’s 16th District is the site of New York’s first COVID-19 “cluster,” and it would become one of the hardest-hit parts of the state as the pandemic progressed. Over the course of the campaign, Bowman and his aides had been hearing from constituents and local activists that Engel did not spend very much time in the district. A poll the campaign conducted in early May found Engel leading Bowman 43% to 13%, but with 43% of voters undecided. The same batch of polling found that shining a light on Engel’s perceived absence from the district resonated more with voters than other negative messages.

But to fully take advantage of Engel’s absenteeism, the campaign wanted independent verification that he was not in the district during the quarantine. It pitched reporters on a research memo documenting Engel’s fight with the state of Maryland to preserve a tax break he received for maintaining his primary residence in the state, and it obtained his address in Potomac, Maryland. A story in The Atlantic added fuel to the fire when the reporter knocked on Engel’s door in upscale Potomac, Maryland, and the congressman answered.  

Another weighty decision by Justice Democrats laid the groundwork for Engel’s “hot mic” moment to seal his fate. The group decided that it would try to pre-empt last-minute attacks from Engel and his allies on the TV airwaves by erecting a super PAC independent of the campaign that would not be subject to the contribution limits ― or disclosure requirements ― of ordinary campaign spending.

To get the project off the ground, Justice Democrats dumped in a sizable chunk of its own grassroots fundraising money and tapped a small network of high-dollar donors, ultimately raising more than $920,000. The Working Families Party joined them in the effort, chipping in more than $400,000. (The identities of the two groups’ donors will become public in July when official disclosures are due.)

Super PACs have long been anathema on the left, given their association with the influence of corporations and wealthy individuals. And Bowman made his refusal to accept corporate PAC money a key point of contrast with Engel. 

But Justice Democrats, which had run an independent digital ad campaign to blast moderate Democrats during the presidential primary, could not rely on other groups to do the heavy lifting for Bowman. The public school principal lacked the mainstream institutional support of other left-wing candidates, such as Texas attorney Jessica Cisneros. Rojas concluded that in the absence of structural changes to the campaign finance system, Justice Democrats needed to do all it could to elect its preferred candidates. 

“We can really say we are using every single tool in our arsenal to put our candidates over the top,” she said.

The independent expenditure effort, led by Helen Brosnan, who helped terminally-ill progressive activist Ady Barkan create a PAC during the 2018 midterm elections, had already prepared a TV spot blasting Engel for staying in Maryland when the “hot mic” moment handed them new material that complemented the narrative they were trying to establish.

Bowman’s allies would end up being on the air defining Engel for at least a week unanswered before the Democratic Majority for Israel PAC began its own TV campaign backing Engel. The pro-Bowman ads were also on television for nine days by the time early in-person voting began on June 13. 

Bowman effectively won the race in that period from late May to mid-June. An internal poll that the campaign publicized on June 17 showed Bowman leading Engel by 10 percentage points ― a remarkable turnaround from early May, when Bowman’s team had kept the figures private. 

“Am I sorry we didn’t get on TV earlier? Yes, I am,” Mark Mellman, executive director of Democratic Majority for Israel, told HuffPost. “That was a very critical period in the campaign.”

Mellman, whose group spent almost $1.6 million trying to reelect Engel, blamed the campaign, however, for failing to define the race on the airwaves on its own. He estimated that his group spent five times as much on television as the campaign spent directly.

“No independent expenditure can make up for candidate and campaign problems,” he said.

Even before Bowman formally jumped in the race, he was aware that Engel’s support for Israeli government policies were likely to become an issue in the race. Engel’s hawkishness on the Israeli-Palestinian conflict, which put him to the right of former President Barack Obama, had earned him critics on the left but deep support from Jewish institutions.

The district’s population is 12% Jewish ― six times more than it is nationally. But, more important, New York’s 16th District is home to large concentrations of Modern Orthodox Jews, many of whom are hard-line Israel backers with records of political giving and organizing to match.

Knowing that he would need to have a better understanding of concerns specific to the Jewish community, Bowman sat down before announcing his run with Rachel McCullough, political director of The Jewish Vote, an arm of the left-wing group Jews for Racial and Economic Justice.

McCullough gave Bowman, who had had limited interactions with the Jewish community up to that point, a crash course on Jewish history and anti-Semitism. Bowman agreed to read JFREJ’s 44-page primer on anti-Semitism and conducted a “book report” for McCullough days later, summarizing what he had learned and analyzing the text’s contents.

“What especially touched him was our analysis of collective trauma and the ways that trauma continues to shape Jewish communities and Jewish politics to this day ― here at home in New York and in Israel-Palestine and beyond,” McCullough recalled. “It really drove home for me that this was a pretty special candidate.”

Bowman also met with Peter Beinart, a seasoned progressive journalist and prominent Jewish critic of the Israeli occupation.  

Although Beinart would not comment on his conversations with Bowman, the Bronx educator ended up adopting positions that mirror Beinart’s. Both men have staked out stances that are well to the left of the Democratic establishment but still shy of the Palestinian solidarity movement’s most radical demands.

Bowman stuck with the mainstream preference for a two-state solution rather than embracing some activists’ desire for a single, bi-national state. And he declined to sign on to the Boycott, Divestment and Sanctions movement, even as he promised to protect its participants’ freedoms before the law. His most ambitious stance was calling to “seriously consider” placing tougher conditions on U.S. financial aid to Israel to better safeguard the human rights of Palestinians and discourage Israeli settlement expansion.

“Especially at this moment when Israel is on the verge of annexing the West Bank and driving a stake into the two-state solution,” putting tighter strings on U.S. aid is “not a radical position,” Beinart said.

In addition, Bowman spoke one-on-one with a number of rabbis in the district, including Steven Exler, who leads the Hebrew Institute of Riverdale, a prominent Modern Orthodox synagogue.

Bowman’s efforts to build relationships in the Jewish community and educate himself on U.S. policy toward Israel did not inoculate him from an offensive launched by pro-Israel groups that totaled $2 million. 

It gave him the tools, however, to respond with confidence and show that the Jewish community was not uniformly behind Engel. The Jewish Vote endorsed Bowman in December, mobilizing more than 100 of its members in New York’s 16th District to form Jews for Jamaal. When a Democratic Majority for Israel PAC ad blasted Bowman for occasionally falling short in his tax payments to New York state over the years, Jews for Jamaal members responded with a video accusing the group of employing racist dog whistles.

In response to an open letter from Exler’s predecessor, Rabbi Avi Weiss, that blasted Bowman for his positions on the Israeli-Palestinian conflict, Bowman penned his own open letter in the Riverdale Press. “I believe firmly in the right of Israelis to live in safety and peace, free from the fear of violence and terrorism from Hamas and other extremists, and support continued U.S. aid to help Israel confront these security challenges,” he wrote. “I also believe that Palestinians are entitled to the same human rights, safety from violence and self-determination in a state of their own.”

Mellman argues that the fallout of the race for the Democratic Party’s more conservative pro-Israel camp is limited because of how little the issue actually came up during the race. But he conceded that Bowman “did work to obfuscate the difference” between his positions on U.S.-Israel relations and Engel’s.

“The average voter would have no way of knowing if there was any difference between the candidates on that issue,” Mellman said.