"Pressley, who became the first woman of color ever elected to the Boston City Council in 2009, has launched her own insurgent primary challenge in MA, taking on longtime Rep. Michael Capuano in the state's 7th Congressional District", Nik DeCosta-Klipa wrote.
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 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.
Ms Pressley argued she would bring new energy and awareness of the needs in the state's only congressional district where a majority of residents are not white. She is not facing a Republican in November.
This win for the hard-left of the Democratic Party against its own establishment comes in the wake of devout socialist Alexandria Ocasio-Cortez's stunning upset win over Rep. Joseph Crowley (D-NY) in New York earlier this summer, a shocker that rocket-fueled the leftist wing of the Democratic Party in a year where establishment incumbents are having a hard time winning re-election.More news: Amazon market value tops $1tn
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There is no Republican on the November ballot in the district, meaning Pressley is virtually assured of entering Congress in January.
"We will vote the same way, but I will lead differently", she said in a recent debate. Pressley called for an "equity agenda" centering around public health, reducing violence, transportation, housing, and advocacy for women.
"This wasn't a battle between a conservative and a liberal, they were both progressives in very good standing", said Peter Ubertaccio, a professor of political science at Stonehill College outside Boston.
However, there are significant differences between the two races.
The 44-year-old's upset over a 10-term incumbent congressman underscores the shift underway in a Democratic Party whose base is seeking younger, more diverse candidates who embrace progressive policies.
Pressley cried tears of joy after receiving the news of her win. And he positioned himself as fervently anti-Donald Trump ― refusing to attend the president's inauguration past year, voting twice in support of impeaching him and frequently calling him out on Twitter.