Zohran Mamdani has won the New York City mayoral race, capping a meteoric rise from a little-known state politician to one of the country's most visible Democratic figures.
The 34-year-old will become the first Muslim mayor of the largest US city.
He defeated Democratic former Governor Andrew Cuomo, 67, who ran as an independent after losing the nomination to Mr Mamdani in the primary election.
Democrats swept a trio of races in the first major elections since President Donald Trump returned to power nine months ago, elevating a new generation of leaders and injecting fresh momentum into the beleaguered party ahead of next year's congressional elections.
Mr Mamdani wasted no time calling out Mr Trump, formally kicking off the battle that will likely define relations between the mayor and the president whose celebrity is tied to the city.
"Donald Trump, since I know you're watching, I have four words for you: turn the volume up!" Mr Mamdani, a Democrat, said in his victory speech.
He told supporters: "If anyone can show a nation betrayed by Donald Trump how to defeat him, it is the city that gave rise to him.
"In this moment of political darkness, New York will be the light.
"And if there is any way to terrify a despot, it is by dismantling the very conditions that allowed him to accumulate power. This is not only how we stop Trump, it's how we stop the next one."
Mr Trump has repeatedly turned the massive powers of the presidency on political rivals, and already before the election had threatened to possibly withhold billions of dollars in federal funding from New York City if Mr Mamdani was elected.
This would follow previous funding cuts by the Trump administration in political moves targeting Democratic congressional leaders also from the city.
"If you have a communist running New York, all you're doing is wasting the money you're sending there," Mr Trump told CBS' 60 Minutes on Sunday, previewing how Republicans will use Mr Mamdani's embrace of a socialist agenda as a line of attack against the Democratic Party.
Mr Mamdani acknowledged his win poses a challenge implementing what he calls "the most ambitious agenda to tackle the cost-of-living crisis this city has seen" since the 1940s - including a proposed rental freeze, universal childcare and other government actions targeting the private sector.
But, in the meantime, Mr Mamdani pledged to fight.
"So hear me, President Trump, when I say this: To get to any of us you will have to go through all of us," he said.
Mr Trump posted a four word response to the win on his Truth Social platform "...AND SO IT BEGINS!"
In Virginia and New Jersey, Democrats Abigail Spanberger, 46, and Mikie Sherrill, 53, won the elections for governor with commanding leads, respectively.
Since President Trump's win last year, Democrats have found themselves locked out of power in Washington and struggling to find the best path out of the political wilderness.
All three candidates emphasised economic issues, particularly affordability.
But both Ms Spanberger and Ms Sherrill hail from the party's moderate wing, while Mr Mamdani campaigned as an unabashed progressive and a new generational voice.
Ms Spanberger, who beat Republican Lieutenant Governor Winsome Earle-Sears, will take over for outgoing Republican Governor Glenn Youngkin.
Both Ms Sherrill and Ms Spanberger had sought to tie their opponents to Mr Trump in an effort to harness frustration among Democratic and independent voters over his chaotic nine months in office.
"We sent a message to the world that in 2025 Virginia chose pragmatism over partisanship," Ms Spanberger said in her victory speech.
"We chose our Commonwealth over chaos," she added.
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Trump threatens to restrict federal funds for New York City if Mamdani wins
Mr Trump gave both candidates some late-stage grist during the ongoing government shutdown.
His administration threatened to fire federal workers - a move with an outsized impact on Virginia, a state adjacent to Washington and home to many government employees.
He also froze billions in funding for a new Hudson River train tunnel, a critical project for New Jersey's large commuter population.
In interviews at Virginia polling stations yesterday, some voters said Mr Trump's most contentious policies were on their minds, including his efforts to deport immigrants who entered the US illegally and to impose costly tariffs on imports of foreign goods, the legality of which is being weighed by the US Supreme Court this week.
Juan Benitez, a self-described independent, was voting for the first time. The 25-year-old restaurant manager backed all of Virginia's Democratic candidates because of his opposition to Mr Trump's immigration policies and the federal government shutdown, for which he blamed Mr Trump.
Voter turnout high
California voted overwhelmingly to redraw its electoral districts in a poll Democrats called to counter efforts by Mr Trump to gerrymander in Republican states.
Early results showed a large majority in the traditionally liberal state voted in favour of a motion that was widely promoted as an opportunity to "stick it to Trump".
Voters approved of Proposition 50 by a margin of two to one, early official results showed, with several major media outlets projecting it would retain a significant majority.
The result is a major win for Governor Gavin Newsom, who is increasingly staking his claim to leadership of the Democratic Party on his willingness to stand up to Mr Trump.
Mr Trump on social media called the vote a scam, suggesting it was rigged without providing evidence.
Turnout appeared high across the board.
In New York City, more than 2 million ballots including early voting were cast, according to the board of elections, the most in a mayoral race since 1969.
Early vote totals in Virginia and New Jersey also outpaced the previous elections in 2021.
In New York, Mr Mamdani has proposed ambitious left-wing policies, including freezing rents for nearly a million apartments and making the city's buses free.
While yesterday's results will offer some insight into the mood of American voters, the midterm elections are a year away, an eternity in politics.
"There's nothing that's going to happen in Virginia or New Jersey that's going to tell us much about what will happen in a congressional district in Missouri or a Senate race in Maine," said Douglas Heye, a Republican strategist.
For Republicans, yesterday’s elections were a test of whether the voters who powered Mr Trump's victory in 2024 will still show up when he is not on the ballot.
But Mr Ciattarelli and Ms Earle-Sears, each running in Democratic-leaning states, faced a conundrum: criticising Mr Trump risked losing his supporters, but embracing him too closely could have alienated moderate and independent voters who disapproved of his policies.
Mr Trump remains unpopular: 57% of Americans disapprove of his job performance, a Reuters/Ipsos poll suggested. But Democrats are not gaining support as a result, with respondents evenly split on whether they would favour Democrats or Republicans in 2026.
