Amid a crowded field in the race to replace retiring state Sen. Susan Fargo, the Lincoln Democrat who’s decided not to seek a ninth term representing the Third Middlesex District, one candidate is riding a recent run of union endorsements.

Since mid-June, Concord Democrat Mara Dolan's campaign has announced receiving support from a number of area unions, including the Massachusetts Coalition of Police, the Boston Teachers Union and the Pipefitters Local 357.

In a press release announcing the Pipefitters Local 357 endorsement, Dolan explains that the protection of collective bargaining rights is a hallmark of her campaign platform. 

“Organized labor makes the middle class strong, and the attacks on labor unions in the last 30 years are directly tied to the weakening of the middle class and of the country,” Dolan said in a statement. “We need to rebuild the foundation for long-term prosperity, and I am the only candidate in this race with labor union endorsements. Labor unions and workers are committed to worker safety, getting the job done right, and building tings to last.”

Dolan is one of five Democrats and seven total candidates seeking the Third Middlesex state senate seat Fargo is vacating after eight terms. The district includes the towns of Bedford, Carlisle, Concord, Lincoln, Waltham, Weston and parts of Lexington and Sudbury.

Other candidates seeking the Third Middlesex seat include Democrats Mike Barrett of Lexington, Joe Kearns Goodwin of Concord, Alex Buck of Chelmsford and Joe Mullin from Weston, and Republicans Greg Howes of Concord and Sandi Martinez from Chelmsford.

In addition to backing from the unions, the Mass Retirees Association and Massachusetts Women’s Political Caucus have also pledged its support for Dolan, a public defender who co-chairs the Massachusetts Democratic State Committee’s committee on public policy.

“We are very proud to endorse Mara Dolan for state senate,” MWPC Executive Director Priti Rao said in a statment. “As a social worker and public defender, she has demonstrated a dedication to public service and an understanding of the needs and issues relevant to the Third Middlesex community. She will be a fantastic advocate for bringing resources back to this community to address the needs of its citizens, from jobs to education. We are looking forward to working with her and think she will make an outstanding addition to the Massachusetts Senate.”