A 10-term incumbent congressman in MA conceded to a progressive candidate during the state's Democratic primaries Tuesday night.
Ms. Pressley, the first black woman elected to the Boston City Council, challenged Mr. Capuano from the left and on style and identity, in a pattern similar to the upset victory of Alexandria Ocasio-Cortez earlier this summer in NY.
She'd be Massachusetts' first black woman in Congress.
During the race, Capuano raised $1.73m to Pressley's $890,000, actively campaigning against her and even cancelling his vacation as soon as he heard she was running.
It's not a sight you see every day, certainly not around Boston - a black woman mounting a plausible challenge to a 10-term white congressman from her own party, a politician with vast connections who votes the progressive line and opposes everything Trump.
Ayanna Pressley just pulled off another stunner.
Those rallying to her cause included Ocasio-Cortez, the political newcomer thrust into the national spotlight when she upended veteran Rep. Joe Crowley, a House Democratic leader, in New York's June 26 primary.
Pressley was endorsed by fellow congressional upstart Alexandria Ocasio-Cortez.
"Oh my god. Oh my god", Pressley said through tears.
A survivor of sexual assault at Boston University and during her childhood, Pressley has been a vocal supporter of victims of sexual violence since long before the #MeToo movement.
Pressley represents the latest underdog candidate to have emerged to challenge both establishment Democrats and Republicans. Pressley's positions are also very progressive.
Pressley tapped into growing cries within the Democratic Party for newer, more diverse leadership.
In a video clip of the moment, her family and staff can be heard shrieking and crying in the background as Pressley begins to hug those around her.
Democratic U.S. Sen. Elizabeth Warren sailed through her primary unopposed.
Other Massachusetts Democratic incumbents held off challengers.
Republican Gov. Charlie Baker won his party's nomination for a second term, defeating Scott Lively, a conservative minister and staunch supporter of Trump who frequently called Baker - a frequent critic of the president - a RINO, or Republican in Name Only. The race focused less on substantive policy differences and more on whether voters wanted a change in the district.