SEEKONK, Mass. (WPRI) — Democrat Jesse Mermell has landed the biggest labor union endorsement of the 4th Congressional District primary so far, announcing Wednesday she’s secured the backing of the SEIU Massachusetts State Council.

The council includes union locals SEIU 509, 1199 SEIU, SEIU 888, SEIU 32BJ, SEIU 3 FO, and the SEIU Committee of Interns and Residents, which together represent roughly 106,500 workers in health care, education, human services and other fields, according to the Mermell campaign, which also announced the endorsement of the Coalition for Social Justice, an advocacy group that has a Fall River field office.

“As the voice of more than 100,000 frontline workers across Massachusetts, the SEIU State Council is proud to unanimously endorse progressive fighter Jesse Mermell for Congress,” FayeRuth Fisher, president of SEIU Massachusetts State Council, said in a statement. “SEIU has worked hand in hand with Jesse over the years to fight for the protections and benefits that the hardworking people of Massachusetts deserve. We know that she will be a true workers’ champion in Congress.”

“SEIU and CSJ are on the frontlines every day standing up for workers,” Mermell said. “Throughout my 20-year career, I have been a frequent partner with both organizations, and now I’m ready to go to DC to continue that partnership as a champion in Congress for working families.”

Mermell, a former top aide to Gov. Deval Patrick who served on the Brookline Select Board, is one of nine Democrats who qualified last week for the Sept. 1 Democratic primary. The 4th District seat is opening up as the incumbent, Joe Kennedy III, moves on to challenge U.S. Sen. Ed Markey. The district stretches from northern Fall River through the Attleboros and Taunton into the Boston suburbs.

While no public polling has been conducted in the race, Mermell is seen as one of the leading contenders in a crowded field.

An internal campaign poll released last week by one of her rivals, Newton City Councilor Becky Grossman, showed Mermell tied for second place with 7% of the vote, the same share as another Newton city councilor, Jack Auchincloss.

The Grossman campaign found a whopping 60% of 4th District primary voters remain undecided in the race, which has struggled to get attention amid the coronavirus pandemic, particularly in the shadow of the marquee Markey-Kennedy bout.

“The headline should read: ‘Undecided is in the lead,’” Shannon Jenkins, a political science professor at the University of Massachusetts Dartmouth, said on WPRI 12’s Newsmakers last weekend.

Mermell is in the middle of the pack on campaign fundraising, taking in $559,533 as of March 31, according to Federal Election Commission filings. That put her behind Alan Khazei, Auchincloss and Grossman, though the Auchincloss campaign has said it’s raised the most specifically for use in the primary.

With so many candidates running and in-person campaigning severely restricted, union backing could be important in the 4th District.

Auchincloss landed the first labor endorsement, from the National Association of Government Employees, and Grossman has the support of the Newton firefighters union as well as the Retired State, County, and Municipal Employees Association of Massachusetts. Mermell herself previously received the support of the Massachusetts State Council of Machinists.

The other Democratic candidates are Brookline residents Dave Cavell, Ihssane Leckey, Natalia Linos and Ben Sigel, and Wellesley resident Christopher Zannetos.

Two Republicans, Julie Hall and David Rosa, have filed for the Republican primary in the 4th District.

Ted Nesi ( is WPRI 12’s politics and business editor and a Target 12 investigative reporter. He is a weekly panelist on Newsmakers and hosts Executive Suite. Follow him on Twitter and Facebook

An earlier version of this article failed to list one of the nine Democratic candidates, Dave Cavell.