On a weirdly warm weekday in November, Boston City Councilor Lydia Edwards stood in East Boston’s Belle Isle Marsh to receive a high-profile boost to her state Senate bid. Boston Mayor Michelle Wu, on only her second day in office, was offering her first endorsement as mayor.

“Lydia is more than a sister to me,” Wu said of her former Boston City Council colleague. “She is a friend, a confidante, a partner, a true partner in this work. … I need Lydia as our partner up at the State House.”

Edwards embraced Wu's backing, citing Boston's new fossil-fuel-divestment ordinance as an example of what she and Wu have accomplished. She added that, if she makes it to the State House, the Edwards-Wu tandem would be "one of the best combinations that's happened for East Boston."

But Edwards' ascent is hardly a sure thing. The Dec. 14 primary for the First Suffolk and Middlesex District pits Edwards and her progressive supporters against Revere School Committe member Anthony D'Ambrosio, who's leaning on support from the district's more conservative communities and running as a political moderate. The election will be a test of Wu's political coattails — and the strength of the movement she represents.

Progressive Democrats have won some big victories in Massachusetts lately, including Ed Markey’s triumph over Joe Kennedy in the 2020 U.S. Senate primary and Wu’s win over Annissa Essaibi George last month. In those wins, individual candidates have benefitted from the support of a powerful coalition that includes like-minded politicians and organizations, committed to using individual electoral triumphs to buoy a broader movement.

The First Suffolk and Middlesex District might seem like fertile ground for this approach. It includes East Boston, more central neighborhoods such as the North End and Beacon Hill, and Cambridgeport on Cambridge's southeastern flank — all areas where Edwards' endorsements from Wu, U.S. Senators Ed Markey, and Congresswoman Ayanna Pressley could prove electorally potent.

Yet the district — which was previously represented by MassBio head Joe Boncore — also includes the entirety of two more conservative communities, the town of Winthrop and the city of Revere. The latter happens to be the hometown of D'Ambrosio, who's making a very different pitch to voters.

“I’m unbeholden to anybody, unbeholden to special interests,” D’Ambrosio said during an interview at his campaign headquarters. “I’m running in order to bring that fresh perspective and that unbeholden nature to the State House. … I’m only going to be accountable to the people in my district.”

Asked if he believes that Edwards is beholden to special interests, D’Ambrosio indicated that he does.

“I see anybody who has raised a tremendous amount of money over a long period of time — three, four, five, six, seven, eight, nine years — as typically tending toward being beholden to special interests, beholden to big donors over time. Because how can you not be?” D’Ambrosio said.

“I do not have that baggage," he added. "I do not have those relationships which would put me in tricky situations when I am going to vote on an issue of severe importance to our district.”

D’Ambrosio, who says he identifies with a "traditional, labor-oriented, working-class ... Democratic ethos," serves on the Revere School Committee. His endorsers include the Revere Teachers Association, the Revere and Winthrop firefighters' unions, and several former and current Revere elected officials, including Mayor Brian Arrigo.

Despite widespread support from the Revere political establishment, Ambrosio isn't a prototypical Revere everyman. While he attended pre-K in the city, his family then moved from Revere to Boxford, and he subsequently attended Phillips Andover Academy, Yale University and the University of Cambridge.

But D'Ambrosio, 25, who currently works as a financial analyst, has crafted a personal narrative that shifts parts of his biography to the background, while centering a localized paean to the American ideal.

“My grandparents came to this country with the shirts on their backs — that’s it,” said D’Ambrosio, whose grandparents settled in East Boston and Winthrop after emigrating from southern Italy. "And they were able to succeed, and provide opportunities for my siblings and I, that they never could have dreamed of in a million years, because their communities uplifted them when they needed help the most.

“It is the American dream,” he added. “It’s something that is fleeting today … but it’s something I intensely believe in, because I feel honored and lucky to be the product of it. And I go to sleep every night, as corny as it sounds, thinking about it.”

Unlike D’Ambrosio, Edwards didn’t grow up in Massachusetts. She graduated from high school on Michigan's Upper Peninsula, where her mother served in the U.S. Air Force and remained after retiring.

Like D’Ambrosio, though, Edwards has a stump speech that features an origin story she's hoping will resonate with voters.

“In this pandemic, while I’m on the one side of the food line handing out the food, if my family were here right now and you saw a little version of Lydia here, she’d be on the other side receiving it,” Edwards said in Belle Isle Marsh.

“I was the girl in school lunch lines [who] would know my family had financial stability depending on which ticket and which order my teacher called us to come get lunch,” she added. “[The teacher] called the A tickets first; they were full-priced tickets. She called the B tickets second, the reduced-price tickets. She called the C tickets third — those were free lunch. … And I would know, if I was a B or C, my mom didn’t have the money that week.”

Edwards, 40, who lives in East Boston, ran unsuccessfully for the First Suffolk and Middlesex seat in 2016 before winning election to the Boston City Council. She’s a graduate of Fordham University and the American University Washington School of Law. In 2014, she led the successful campaign to pass a domestic workers’ bill of rights in Massachusetts.

While both candidates say they’re concerned with climate change and climate resiliency, their legislative visions differ. D’Ambrosio says he'd focus on educational issues, and that he would push legislation to increase affordable broadband access for families in the district.

“I would be supportive — immediately — of legislation that beefs up our broadband-infrastructure capabilities, and really treats broadband as a public utility. That allows our citizens, our children, our students to access their education and potential jobs of the future right now,” he said.

Edwards’ legislative to-do list includes equitably distributing forthcoming federal funds from the American Rescue Plan Act; passing the CROWN Act, which would prohibit discrimination based on hair texture and style; and passing a statewide version of Boston’s Trust Act, which limits local law enforcement’s cooperation with federal immigration authorities.

During her time on the Boston City Council, Edwards said, "We fought to make sure that our local police and immigration [enforcement] are separate. Well, that doesn’t do you any good if you cross over the border into another town. … I believe that people should drive with dignity and respect, that people’s right to move should be understood as a fundamental right, and that drivers’ licenses should be given to everyone.”

Recent filings with the Massachusetts Office of Campaign and Political Finance suggest a competitive race heading into the Dec. 14 primary. From July through November, Edwards raised about $210,000 and spent close to $180,000. D'Ambrosio has raised nearly $190,000 and spent almost $150,000.

No Republican is on the ballot, so the Democratic nominee will almost certainly join the Senate next year.