A millennial candidate has shaken up the US Democratic Party by defeating the incumbent congressman for his seat.
Alexandria Ocasio-Cortez, 28, defeated political veteran Joe Crowley, 56, on Tuesday night in their party's congressional primary in New York City.
Mr Crowley, a 10-term Democrat, had been tipped as a future party leader or even Speaker of the House.
Ms Ocasio-Cortez, a former Bernie Sanders volunteer from a Puerto Rican family, won with 57.5 percent of the vote.
Mr Crowley had not faced a challenger from his own party in 14 years in the mostly ethnic minority district, which covers parts of the Bronx and Queens in New York.
Ms Ocasio-Cortez will now face Republican candidate Anthony Pappas in the November mid-terms.
If she wins, she will become the youngest ever woman elected to Congress.
She led a progressive campaign, supporting universal healthcare, tuition-free college and criminal justice reform.
Following Ms Ocasio-Cortez's win, dictionary Merriam-Webster tweeted that socialism emerged as their top search item.
'Socialism' has been our top search since Alexandria Ocasio-Cortez's primary win last night. https://t.co/0WzzemkF6Y— Merriam-Webster (@MerriamWebster) June 27, 2018
The political novice, who describes herself as a socialist Democrat, had huge grassroots support.
She raised more small-dollar donations than any other New York City congressional candidate.
In fact she found little support from established Democrats.
Senator Kirsten Gillibrand, a top Democrat who has a political action committee designed to support women candidates, endorsed her opponent Mr Crowley.
Ms Ocasio-Cortez posted on Twitter after Ms Gillibrand's endorsement that the New York senator "didn't even bother to talk to nor consider me before endorsing".
Warning shots fired
Analysis by Anthony Zurcher, BBC News
The progressive left just fired a warning shot across the bow of the Democratic Party establishment.
Congressman Joe Crowley was seen as a potential future speaker of the House of Representatives.
Now he is taking a forced exit from politics, paying tribute to the young activist who defeated him with a rendition of Bruce Springsteen's Born to Run after conceding defeat.
Up until now, it seemed like Democratic incumbents had been insulated from the anger and energy that has coursed through the political left during the Trump presidency.
New candidates - many younger, many women - were running for office, but they were mostly winning open primary contests or losing to better-funded, better-known Democratic incumbents.
That may have just changed.
The rage among the liberal base - stoked by heart-rending accounts of children separated from their parents at the US-Mexico border - has led to new bursts of activism, confrontation and, perhaps, an anti-establishment fervour that could endanger seemingly safe Democratic politicians.
The party is moving to the left, with growing support for universal healthcare and free college education - issues that were at the heart of Senator Bernie Sanders' 2016 presidential campaign.
That will shape the coming mid-term congressional primaries, and prospective 2020 Democratic presidential candidates will certainly take note.
Unsurprising, but disappointing that @SenGillibrand didn’t even bother to talk to nor consider me before endorsing.— Alexandria Ocasio-Cortez (@Ocasio2018) June 11, 2018
You‘d think a progressive leader would at least be interested in how a no-corporate money Bronx Latina triggered the 1st NY-14 primary in 14 years on prog issues. https://t.co/A5ZswcUpW9
During her campaign, she criticised Mr Crowley for his ties to Wall Street and accused him of being out of touch with his increasingly diverse constituents.
They thanked each other after the result, with Mr Crowley saying he would support Ms Ocasio-Cortez in the mid-terms.
Joe Crowley (@JoeCrowleyNY) is playing guitar and singing "Born to Run", dedicated to the candidate who just primaried him, Alexandria Ocasio-Cortez (@Ocasio2018)— Holly Figueroa O'Reilly BWCS (@AynRandPaulRyan) June 27, 2018
Classy af. Well done, sir.#NY14pic.twitter.com/qYOcb9CdE0
At his concession speech, Mr Crowley played guitar, dedicating the song Born to Run by Bruce Springsteen to Ms Ocasio-Cortez.
Today I saw people voting that are almost never seen in an off-year midterm primary.— Alexandria Ocasio-Cortez (@Ocasio2018) June 27, 2018
Just now, as I’m typing this with 8 minutes left, two young men of color, 20 years old, just walked up to me and said they just voted.
2 yrs ago, the “experts” told me not to bother with them.
Political analysts see her 15-percentage-point victory as the biggest political upset within a party since Republican House Majority Leader Eric Cantor lost in 2014 to a little-known right-wing professor, Dave Brat.
Ms Ocasio-Cortez is now one of 130 women who have won primary elections for US House seats, 80 percent of who are Democrats.
There are still 341 women in the running in the House of Representatives - a record high, according to the latest data from the Center for Women and American Politics.