After a divisive campaign marked by fierce clashes over immigration, race and other cultural issues, millions of Americans cast their votes Tuesday to determine the balance of power in Congress and shape the future of Donald Trump's presidency. The significant increase in the number of Americans who took part in early voting, over 40 million, the obvious enthusiasm among the youth, women and minorities to take part in heated campaigns, Trump's whirlwind rallies across the country that lasted up until late Monday, and counter rallies held by former Democratic president Barack Obama, were only a few indicators of how Americans understood the significance of Tuesday's congressional elections. The first national elections since Trump captured the White House in a stunning 2016 upset was in fact a referendum on the polarising Republican president and his hardline policies, and a test of whether Democrats can turn the energy of the liberal anti-Trump resistance into victories at the ballot box. “Everything we have achieved is at stake tomorrow,” Trump told supporters Monday night in Fort Wayne, Indiana, at one of his three rallies to stoke turnout on the last day before voting. All 435 seats in the US House of Representatives, 35 US Senate seats and 36 governorships were up for grabs Tuesday in elections focused on dozens of competitive races from coast to coast that opinion polls show could go either way. Final results were pending as Al-Ahram Weekly went to print early Wednesday, but most election forecasters predicted that Democrats were favoured to pick up the minimum of 23 House seats they need for a majority, which would enable them to stymie Trump's legislative agenda and investigate his administration. Meanwhile, Republicans were expected to retain their slight majority in the US Senate, currently at two seats, which would let them retain the power to approve US Supreme Court and other judicial nominations on straight party-line votes. But at least 64 House races remain competitive, according to a Reuters analysis of the three top nonpartisan forecasters, and Senate control was expected to come down to a half dozen close contests in Arizona, Nevada, Missouri, North Dakota, Indiana and Florida. Democrats also threatened to recapture governor offices in several battleground states such as Michigan, Wisconsin and Ohio, a potential help for the party in those states in the 2020 presidential race. In a last-minute controversy, NBC, Fox News and Facebook on Monday pulled an ad by Trump's campaign that critics had labelled racist. The 30-second spot featured courtroom video of an illegal immigrant from Mexico convicted in the 2014 killings of two police officers, juxtaposed with scenes of migrants headed through Mexico. Critics, including members of Trump's own party, had condemned it as racially divisive. CNN already had refused to run the ad, saying it was “racist”. Voter turnout was expected to be the highest for a midterm election in 50 years, experts predicted. About 40 million early votes were likely cast, said Michael McDonald, a professor at the University of Florida who tracks the figures. In the last such congressional elections in 2014, there were 27.5 million early votes. During a whirlwind six-day blitz to wrap up the campaign, Trump repeatedly raised fears about immigrants, issuing harsh warnings about a caravan of Central American migrants moving through Mexico towards the US border. A debate about whether Trump's biting rhetoric encouraged extremists erupted in the campaign's final weeks after pipe bombs were mailed to his top political rivals allegedly by a Trump supporter who was arrested and charged, while separately 11 people were fatally shot at a Pittsburgh synagogue. But on the eve of the election, the president said in an interview with Sinclair Broadcasting that he wished he had a softer tone during his first two years in office — even as he continued his relentless attacks on political rivals. Trump blamed the political vitriol on election season. “I'd love to get along and I think after the election a lot of things can happen,” Trump said. “But right now they're in their mode and we're in our mode.” Many Democratic candidates in tight races shied away from harsh criticism of Trump, focusing instead on bread-and-butter issues like maintaining insurance protections for people with pre-existing medical conditions and safeguarding the Social Security retirement and Medicare healthcare programmes for senior citizens. But in rather unusual campaigning by a former president who had only left office two years ago, Obama hit the campaign trail in the election's final days to challenge Trump, questioning his policies and character. “How we conduct ourselves in public life is on the ballot,” Obama told Democratic volunteers in suburban Virginia who were working for Senator Tim Kaine and House candidate Jennifer Wexton, who is challenging incumbent Republican Barbara Comstock. In reality, many analysts believe that two Americas could render diametrically opposed verdicts on Trump's tumultuous first two years in Tuesday's election. From one direction, Trump faces intense antipathy among young people and minority voters and unusually broad resistance among college-educated white voters, especially women. That threatens Republicans with widespread losses in well-educated, often racially diverse, suburbs in major metropolitan areas around the country, as well as the possible loss of Senate seats in the diverse and growing Southwest states of Nevada, Arizona and possibly (though less likely) Texas. On the other side, Trump retains strong support among evangelical, rural and non-college-educated white voters, including women. Trump has energised these voters with a campaign closing argument that appeals to white racial fears and resentments more overtly than any national political figure since George Wallace in the late 1960s. Trump's efforts are aimed primarily at reinforcing Republican opportunities to oust incumbent Democratic senators in several older, preponderantly white interior states that voted for him in 2016. The high energy among Trump's base is also sustaining long-shot Republican hopes of narrowly holding the House — or at least minimising any Democratic majority — by maintaining the GOP's control of most exurban and blue-collar seats outside the major metropolitan areas. The result could be a bifurcated midterm result that simultaneously repudiates Trump while providing him some reaffirmation. While most debate has focused on whether a backlash to Trump will spur a “wave” of Democratic gains, Tuesday's election seems more likely to solidify and even deepen the stark geographic and demographic divisions that marked Trump's election in 2016. The prospect that turnout will vastly exceed the level in 2014, the most recent midterm election, by perhaps 20 million votes or more underscores the sense that this campaign may mark a new peak in the partitioning of American society between two political coalitions separated above all by whether they welcome or fear the profound demographic, cultural and economic changes remaking US life.