Cori Bush, a once homeless racial justice activist, ousted a 10-term political veteran in the Missouri Democratic primary.
She beat Congressman William Lacy Clay 49% – 46%. Either Mr. Clay or his father, a civil rights activist, has occupied the seat since the 1960s.
Ordinary minister and former nurse, Mrs. Bush would be the first black woman to represent Missouri in Congress.
His victory is the latest upheaval against the establishment Democrats by the newcomers.
She had campaigned for Senator Bernie Sanders during her presidential race.
Praising her on Twitter, Sanders said Ms. Bush “will face this country’s business elite when she comes to Congress.”
Ms Bush, 44, lost to Mr Clay, 64, in the 2018 primary in Missouri.
Mr. Clay is a long-time legislator who has represented the St. Louis area for two decades. His father is a co-founder of the Congressional Black Caucus.
- A simple guide to America’s primaries and caucuses
- I’m running for office because of George Floyd
Mr. Clay campaigned on his record in Congress while pointing out Ms. Bush’s lack of political experience.
His first victory almost guarantees him a place in Congress, representing the strongly Democratic district.
This follows a number of jolts in the 2020 electoral cycle. In June, Foreign House Speaker Eliot Engel lost his seat in New York City to college principal Jamaal Bowman.
- Newcomer defeats Trump candidate for congressional primary
- Political outsider shakes New York’s ‘status quo’
The victories show the influence of the Democratic left ahead of the November presidential election, where moderate Joe Biden will face Republican President Donald Trump.
Ms Bush spoke to supporters on Tuesday, saying many people expected her to lose.
“They counted us out,” she said, according to CBS News. “I’m just the protester, I’m just the activist with no name, no title and no real money. That’s all they said I was. But St. Louis has come today. ”
Mrs Bush had to quit her job at a nursery school when she fell ill while pregnant with her second child in 2001. She and her then husband were kicked out of their home and – along with their baby and their young son – are homeless for several months. , living out of their car. The couple eventually divorced.
Ms. Bush has since graduated as a nurse and became a pastor, before also becoming a racial justice activist. Ms Bush led protests in Ferguson in 2014, following the police murder of unarmed 18-year-old black Michael Brown.
During her 2020 campaign, she was backed by Justice Democrats, who campaigned for her friend and progressive compatriot Alexandria Ocasio-Cortez in 2018.
The Justice Democrats group hailed his victory as a “Black Lives Matter organizer” defeating “a political dynasty backed by business”.
- How BLM went from Facebook publishing to the global movement
- Who will Biden choose as his running mate?
Primary elections were also held Tuesday in Michigan, Arizona, Kansas and Washington state.
Former Kansas Secretary of State Kris Kobach lost the Republican Senate primary elections to more moderate Congressman Roger Marshall.
The result is a relief for Republicans, who feared that a victory for Mr. Kobach, a controversial Tory, could overthrow the Senate seat.
Mr Kobach lost the 2018 gubernatorial race to Democratic candidate Laura Kelly despite President Trump’s backing.
In Michigan, Democratic Congresswoman Rashida Tlaib won her rematch with Detroit City Council President Brenda Jones with 90 percent of the votes counted. Ms Tlaib won 66% of the vote against 33% for Ms Jones.
- Palestinian dress worn in the new US Congress
- Who are the delegates called “the squad”?
Ms. Tlaib is a member of the first-term progressive congress group known as “the team”, along with Ms. Ocasio-Cortez.
“Voters have sent a clear message that they are done waiting for transformative change, that they want an unapologetic fighter who will take the status quo and win,” Tlaib said in a statement to US media.