Harris leads among women, Trump among men, polls showTrump may declare victory on election night despite uncounted ballotsHarris would be first woman, Black woman, South Asian American presidentControl of Congress also at stake with Republicans having easier Senate pathThe dizzying presidential contest between Republican Donald Trump and Democrat Kamala Harris hurtled toward an uncertain finish on Tuesday as millions of Americans headed to the polls to choose between two sharply different visions for the country.A race whipsawed by unprecedented events – two assassination attempts against Trump, President Joe Biden's surprise withdrawal and Harris' rapid rise – remained too close to call, even after billions of dollars in spending and months of frenetic campaigning.The first ballots cast on election day mirrored the nationwide divide. Overnight, the six registered voters in the tiny hamlet of Dixville Notch, New Hampshire, split their votes between Harris and Trump in voting just past midnight.Elsewhere on the East Coast, polls began opening at 7 a.m. (1200 GMT) in more than two dozen states.Trump's campaign has suggested he may declare victory on election night even while millions of ballots have yet to be counted, just as he did four years ago. The former president has repeatedly said any defeat could only stem from widespread fraud, echoing his false claims from 2020. The winner may not be known for days if the margins in key states are as slim as expected.No matter who wins the White House, history will be made.Harris, 60, the first female vice president, would become the first woman, Black woman and South Asian American to win the presidency. Trump, 78, the only president to be impeached twice and the first former president to be criminally convicted, would also become the first president to win non-consecutive terms in more than a century.Opinion polls in the campaign's final days have shown the candidates running neck-and-neck in each of the seven states likely to determine the winner: Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania and Wisconsin.Reuters/Ipsos polling shows a significant gender gap, with Harris leading among women by 12 percentage points and Trump winning among men by 7 percentage points.The contest reflects a deeply polarized nation whose divisions have only grown starker during a fiercely competitive race. Trump has employed increasingly dark and apocalyptic rhetoric on the campaign trail. Harris has urged Americans to come together, while also warning that a second Trump term would threaten the very underpinnings of American democracy.Control of both chambers of Congress is also up for grabs. Republicans have an easier path in the US Senate, where Democrats are defending several seats in Republican-leaning states, while the House of Representatives looks like a toss-up.The candidates spent the final weekend barnstorming the swing states in search of every available vote. Trump staged his final rally on Monday evening in Grand Rapids, Michigan, while Harris held twin rallies in Pittsburgh and Philadelphia.More than 80 million Americans had already voted before Tuesday, either via mail or in person, according to the University of Florida Election Lab.During the campaign, Trump hammered first Biden and then Harris for their handling of the economy, which polls show is at the top of voters' concerns despite low unemployment and cooling inflation. But he showed a characteristic inability to stay on message, at one point questioning Harris' Black identity and vowing to protect women ‘whether they like it or not’.His unbridled approach seemed designed to fire up his supporters, rather than expand his appeal. Even more than in 2016 and 2020, Trump has demonized immigrants who crossed the border illegally, falsely accusing them of fomenting a violent crime wave, and he has vowed to use the government to prosecute his political rivals.Polls show he has made some gains among Black and Latino voters, despite the historic nature of Harris' candidacy. Trump has often warned that migrants are taking jobs away from those constituencies.By contrast, Harris has tried to piece together a broader but challenging coalition of liberal Democrats, independents and disaffected moderate Republicans, describing Trump as too dangerous to elect.She campaigned on protecting reproductive rights, an issue that has galvanized women since the US Supreme Court in 2022 eliminated a nationwide right to abortion.Harris has faced anger from many pro-Palestinian voters over the Biden administration's military and financial support for Israel's war in Gaza. While she has not previewed a shift in US policy, she has said she will do everything possible to end the conflict.After Biden, 81, withdrew amid concerns about his age, Harris sought to turn the tables on Trump, pointing to his rambling rallies as evidence he is unfit. Her campaign's embrace of viral memes and a parade of celebrity endorsements gained her traction with young voters seen as a critical voting bloc.Trump countered the likes of Harris supporters Taylor Swift and Beyonce with Elon Musk, the world's richest man, who played an increasingly visible role as a surrogate and a top donor to Trump's cause.Tuesday's vote follows one of the most turbulent half-years in modern American politics.In May, a New York jury found Trump guilty of falsifying business records to hide hush money payments to a porn star. Four weeks later, Trump and Biden met for their only debate, where the incumbent president delivered a disastrous performance that supercharged voters' existing concerns about his mental acuity.In July, Trump narrowly escaped a would-be assassin's bullet at a Pennsylvania rally, just before the Republican National Convention. Barely a week later, Biden exited the race, bowing to pressure from Democratic leaders.Harris' entry into the race re-energized her party, and she raised more than $1 billion in less than three months while erasing Trump's lead over Biden in public polls.