A political newcomer in New York has sent a shockwave through the Democratic party establishment by declaring victory over a 31-year incumbent.
Jamaal Bowman, 44, a former Bronx school principal, has a solid lead over Eliot Engel in the 16th district.
His campaign is being likened to Alexandria Ocasio-Cortez’s stunning victory in a neighbouring New York congressional district two years ago.
Final results may take weeks, but Mr Bowman’s lead appears insurmountable.
Tuesday’s primary elections tested the influence of the Democratic left wing at a time when its standard-bearer for November’s presidential election will be a moderate, Joe Biden.
As of Wednesday, Mr Bowman had captured 60.7% of the vote, compared to Mr Engel’s 34.7%, according to preliminary figures from the state board of elections.
In the liberal-leaning New York district, whoever wins the primary is all but assured to beat his Republican opponent in autumn’s general election.
“I’m a Black man raised by a single mother in a housing project. That story doesn’t usually end in Congress,” Mr Bowman, 44, tweeted on Wednesday.
“But today, that 11-year-old boy beaten by police is about to be your Representative.
“I can’t wait to get to DC and cause problems for those maintaining the status quo.”
But Mr Engel – who is chairman of the House of Representatives Foreign Affairs Committee – did not concede, with his campaign citing a record number of yet-uncounted absentee ballots because of the coronavirus pandemic.
Mr Bowman ran on a platform focusing on racial justice, calling for the defunding of law enforcement, an idea seen by party moderates as too radical this election season.
Mr Bowman won the endorsements of progressive darlings Senator Bernie Sanders, Senator Elizabeth Warren and Ms Ocasio-Cortez.
Mr Engel, a 16-term congressman, was endorsed by Hillary Clinton, House Speaker Nancy Pelosi and the Congressional Black Caucus.
Mr Engel, 73, did not help himself when he was overheard in early June on a microphone at a news conference devoted to Black Lives Matter saying he had only turned up because of his looming election.
“If I didn’t have a primary,” he said, “I wouldn’t care.”
Ms Ocasio-Cortez herself brushed aside a challenge on Tuesday in her New York City district from former CNBC television anchor Michelle Caruso-Cabrera, 53.
Ms Ocasio-Cortez amassed about 70% of the vote. Her opponent, who was backed by the conservative-leaning US Chamber of Commerce, won less than 20% of ballots.
The liberal leading light was a 28-year-old former waitress when she caused a political earthquake two years ago by defeating Joe Crowley, a senior House Democrat who had held the 14th district for two decades.
It was a rewarding night for at least one other black progressive after a primary campaign waged amid anti-racism protests stemming from the police killing of an unarmed black man, George Floyd, in Minneapolis, Minnesota, last month.
In central Virginia, Cameron Webb decisively beat three white opponents in the primary for a US House seat that Democrats hope to win from Republicans. He would be the first African American physician in Congress if elected in November.
In Kentucky, meanwhile, another black progressive, Charles Booker, hopes to beat establishment favourite Amy McGrath to become the Democratic Senate candidate.
The well-financed Ms McGrath had the edge over Mr Booker in early results, but hundreds of thousands of absentee ballots are outstanding and final results will not be known until next week at the earliest.