Mr. Capuano conceded the race to Ms. Pressley on Tuesday night, though the Associated Press had yet to declare a victor in the race. In 2009, she was the first woman of colour ever elected to the Boston City Council.
Pressley conceded throughout the race that there was little policy daylight between her and Capuano, though she did go further than him by calling for the abolishment of the Immigrations and Customs Enforcement agency. Robert Pittenger, R-N.C.; Mark Sanford, R-S.C., and fellow 10-term Rep. Joe Crowley, D-N.Y.
The last time an incumbent Democratic House member lost a primary was in 2014, when Seth Moulton defeated former Rep. John Tierney, who brought significant personal baggage to the campaign.
"Change is coming and the future belongs to all of us", Pressley told wildly cheering supporters Tuesday night.More news: NFL Backs Nike’s Colin Kaepernick Ad
In a video posted by her close friend Jesse Mermell, Pressley stands up in seeming disbelief.
During the campaign, Capuano touted his credentials as an "unabashed liberal", but he found himself competing with Pressley over who was the more progressive candidate.
In the general election, Ms. Pressley will be heavily favored in the 7th Congressional District, which covers parts of Boston and its heavily Democratic suburbs and that backed Hillary Clinton with 84 percent of its vote in the 2016 presidential race.
Pressley, who represents the 7th district, one of Massachusetts' most diverse, has advocated for a progressive agenda, which includes abolishing ICE, increased mental health care services in schools and medicare for all.More news: Nadal sees off Basilashvili to reach U.S. Open quarters
Pressley's win echoed that of Alexandria Ocasio-Cortez's over the long-time representative Joe Crowley in NY, and the ascent of Stacey Abrams in Georgia, who - if she wins - will become the first African-American female governor in USA history.
Rep. William Keating easily fended off a challenge from his left in his bid for a fifth term.
Galvin will face Republican Anthony Amore in November.More news: Djokovic has sympathy for 'very positive' umpire Lahyani after Kyrgios controversy
Capuano was endorsed by prominent MA figures, including former Gov. Deval Patrick, the state's first black governor. Both contended that Baker's support among voters was soft and that his administration had failed to make significant strides in many areas, particularly the problems plaguing the Boston-area transit system known as the "T".