As a Philadelphia Democrat whose campaigns have been backed by a conservative billionaire promoting “school choice” policies like charter expansion, State Sen. Anthony H. Williams has long had a unique role in the debate over education policy in Pennsylvania.

In the past, those debates have taken place on larger stages, such as his unsuccessful campaigns for governor in 2010 and mayor in 2015.

But on Tuesday it will play out for the first time in Williams’ backyard when he faces off against Paul Prescod, an organizer with the Democratic Socialists of America who left his job as a Philadelphia public school teacher to run against Williams in the Democratic primary for the Pennsylvania Senate’s 8th District.

Williams has never faced a serious challenger since winning the seat in a 1998 election orchestrated by his late father, Hardy Williams, who founded a powerful Black political organization based in West and Southwest Philadelphia that his son now leads.

Prescod, who taught at the Kensington Health Sciences Academy, said he was motivated to run after “seeing and experiencing the disinvestment for the public schools and the real crisis point that it’s at.”

“Especially on this issue of education, I felt there needed to be a different voice and a different choice,” said Prescod, 31, adding that the “school choice” programs Williams supports sap resources from traditional public schools.

Williams, 64, said that the most important issue in this election is not education but public safety, and that his experience in Harrisburg and in the district makes him better equipped to tackle it.

“Climate, environment, jobs, employment, education are all important issues, but fundamental to my district is how we remove illegal guns from Philadelphia and the region,” Williams said, adding that Prescod is ill-prepared because he doesn’t have as many connections with people “who are actively pursuing solutions to the problems.”

The race remains an uphill battle for Prescod, a first-time candidate running in an area where voters have been casting ballots for Williams or his father for 50 years. But Prescod has gained a surprising amount of traction, raising more than $300,000 and winning endorsements from the Philadelphia Federation of Teachers; Philadelphia’s District Council 33 of the American Federation of State, County and Municipal Employees; and the progressive group Reclaim Philadelphia.

Williams has taken in more than $500,000, including significant contributions from his Democratic colleagues in the Senate, the building trades unions, and a slew of corporations, law firms, and lobbyists.

Beyond being a referendum over Williams’ tenure, the race is also a test of the potential reach of Philadelphia’s progressive movement, which since 2016 has won a string of victories against establishment-backed Democrats but has rarely contested for a seat as racially and economically diverse as Williams’.

The 8th District, which is 58% Black, includes parts of Delaware County, West Philadelphia, and Southwest Philadelphia. The legislative seats progressives have captured in recent elections have typically been in gentrifying neighborhoods with a disproportionate share of highly educated, young, white voters.

“The district has a little bit of everything, and I do think it’s kind of unchartered territory for the left,” Prescod said. “There hasn’t been a campaign in a district like this.”

Within the ever-changing factions and alliances of the Philadelphia progressive movement, the race is also notable as a sign of the increased ambitions of the local DSA, which has previously taken a backseat to other progressive organizations when it comes to electoral politics. Prescod has led the Philly DSA’s labor committee, and his candidacy has been boosted by nearly 200 volunteers from the group who have canvassed the district and called voters on his behalf.

In other cities, local chapters of the DSA have been leaders of political organizations on the left, most famously by helping to elect Alexandria Ocasio-Cortez to a Bronx-based congressional seat in 2018. But until this year, other progressive organizations like Reclaim Philadelphia have led the charge.

Williams has tried to seize on Prescod’s ties to the left to bolster a narrative that the challenger is an outsider to the district, saying that Prescod’s campaign is “a part of gentrification politics.”

Prescod, however, makes for an odd target for carpetbagging accusations. A Norristown native and Temple University graduate, Prescod said he grew up “lower-middle class” and lives in the Cedar Park section of West Philadelphia.

Williams, who is Black and lives on Cobbs Creek Parkway, has also invoked Prescod’s race. Prescod, who identifies as multiracial, is the son of a Black man from Barbados and a white woman.

“He always mentions his father is Trinidadian. He never mentions his mom,” Williams said, misidentifying Prescod’s father’s nationality. “You’re doing code word because you don’t mention your mother because she’s probably not Trinidadian.”

Prescod noted that Williams, who attended the elite Westtown School in West Chester and graduated from Franklin & Marshall College, had a more privileged upbringing.

“It’s just an effort to delegitimize me,” Prescod said. “Let’s be real. Williams went to a private school.”

Prescod said that it is Williams who is out of touch with the district because of the campaign money he receives from Jeffrey Yass, a Main Line hedge fund operator who is the richest person in Pennsylvania and who has spent millions funding committees and candidates who back school choice policies.

“Who is he really accountable to?” Prescod said. “We just can’t ignore the influence of the money he takes from people like Jeffrey Yass.”

Williams noted that he also received backing from labor unions and questioned why he should have to turn down money from a donor.

“Frankly, I’m stunned that I’m even being confronted with these questions about that,” Williams said. “I’m supposed to tie my hands behind my back and not have support from people who have support for my issues that they agree with me on because their name is Yass?”

The base salary for state senators in Pennsylvania is $95,000 per year. No Republicans are running in the heavily Democratic district, and the winner of Tuesday’s primary will serve a four-year term beginning in January.