Joe Biden is leading by his widest-set margin among Democratic presidential contenders since his campaign's launch in April, according to a new poll from CNN.

More than 35 per cent of Democrat and Democrat-leaning voters support the former vice president, compared to other frontrunners Elizabeth Warren, who polled at 19 per cent, and Bernie Sanders, who was on 16 per cent.

SSRS surveyed 1,003 people over three days in October; 352 were called on a landline and 651 responded via mobile phone.

South Bend, Indiana Mayor Pete Buttigieg and California Senator Kamala Harris each received 6 per cent, and Minnesota Senator Amy Klobuchar and former Texas Congressman Beto O'Rourke each polled at 3 per cent.

The Democrat challengers to Trump in 2020 Show all 25 1 /25 The Democrat challengers to Trump in 2020 The Democrat challengers to Trump in 2020 Bernie Sanders The Vermont senator has launched a second bid for president after losing out to Hilary Clinton in the 2016 Democratic primaries. He is running on a similar platform of democratic socialist reform Getty The Democrat challengers to Trump in 2020 Joe Biden The former vice president recently faced scrutiny for inappropriate touching of women, but was thought to deal with the criticism well and has since maintained a front runner status in national polling EPA The Democrat challengers to Trump in 2020 Elizabeth Warren The Massachusetts senator is a progressive Democrat, and a major supporter of regulating Wall Street Reuters The Democrat challengers to Trump in 2020 Amy Klobuchar Klobuchar is a Minnesota senator who earned praise for her contribution to the Brett Kavanaugh hearings Getty The Democrat challengers to Trump in 2020 Michael Bloomberg Michael Bloomberg, a late addition to the 2020 race, announced his candidacy after months of speculation in November. He has launched a massive ad-buying campaign and issued an apology for the controversial "stop and frisk" programme that adversely impacted minority communities in New York City when he was mayor Getty Images The Democrat challengers to Trump in 2020 Tulsi Gabbard The Hawaii congresswoman announced her candidacy in January, but has faced tough questions on her past comments on LGBT+ rights and her stance on Syrian President Bashar al-Assad Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Pete Buttigieg The centrist Indiana mayor and war veteran would be the first openly LGBT+ president in American history Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Deval Patrick The former Massachusetts governor launched a late 2020 candidacy and received very little reception. With just a few short months until the first voters flock to the polls, the former governor is running as a centrist and believes he can unite the party's various voting blocs AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Beto O'Rourke The former Texas congressman formally launched his bid for the presidency in March. He ran on a progressive platform, stating that the US is driven by "gross differences in opportunity and outcome" AP The Democrat challengers to Trump in 2020 DROPPED OUT: Kamala Harris The former California attorney general was introduced to the national stage during Jeff Sessions’ testimony. She has endorsed Medicare-for-all and proposed a major tax-credit for the middle class AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Bill De Blasio The New York mayor announced his bid on 16 May 2019. He emerged in 2013 as a leading voice in the left wing of his party but struggled to build a national profile and has suffered a number of political setbacks in his time as mayor AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Steve Bullock The Montana governor announced his bid on 14 May. He stated "We need to defeat Donald Trump in 2020 and defeat the corrupt system that lets campaign money drown out the people's voice, so we can finally make good on the promise of a fair shot for everyone." He also highlighted the fact that he won the governor's seat in a red [Republican] state Reuters The Democrat challengers to Trump in 2020 DROPPED OUT: Cory Booker The New Jersey Senator has focused on restoring kindness and civility in American politics throughout his campaign, though he has failed to secure the same level of support and fundraising as several other senators running for the White House in 2020 Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Wayne Messam Mayor of the city of Miramar in the Miami metropolitan area, Wayne Messam said he intended to run on a progressive platform against the "broken" federal government. He favours gun regulations and was a signatory to a letter from some 400 mayors condemning President Trump's withdrawal from the Paris Climate Accord Vice News The Democrat challengers to Trump in 2020 DROPPED OUT: Kirsten Gillibrand The New York Senator formally announced her presidential bid in January, saying that “healthcare should be a right, not a privilege” Getty The Democrat challengers to Trump in 2020 DROPPED OUT: John Delaney The Maryland congressman was the first to launch his bid for presidency, making the announcement in 2017 AP The Democrat challengers to Trump in 2020 DROPPED OUT: Andrew Yang The entrepreneur announced his presidential candidacy by pledging that he would introduce a universal basic income of $1,000 a month to every American over the age of 18 Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Julian Castro The former San Antonio mayor announced his candidacy in January and said that his running has a “special meaning” for the Latino community in the US Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Marianne Williamson The author and spiritual adviser has announced her intention to run for president. She had previously run for congress as an independent in 2014 but was unsuccessful Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Eric Swalwell One of the younger candidates, Swalwell has served on multiple committees in the House of Representatives. He intended to make gun control central to his campaign but dropped out after his team said it was clear there was no path to victory Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Seth Moulton A Massachusetts congressman, Moulton is a former US soldier who is best known for trying to stop Nancy Pelosi from becoming speaker of the house. He dropped out of the race after not polling well in key states Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Jay Inslee Inslee has been governor of Washington since 2013. His bid was centred around climate change AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: John Hickenlooper The former governor of Colorado aimed to sell himself as an effective leader who was open to compromise, but failed to make a splash on the national stage Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Tim Ryan Ohio representative Tim Ryan ran on a campaign that hinged on his working class roots, though his messaging did not appear to resonate with voters Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Tom Steyer Democratic presidential hopeful billionaire and philanthropist Tom Steyer is a longtime Democratic donor AFP/Getty

According to the SSRI poll, published on Wednesday, the centrist-leaning former vice-president is receiving most of his support among moderate and conservative Democrats, up from 29 per cent in September to 43 per cent in October, and nonwhite voters, who spiked their support from 28 per cent to 42 per cent within the last month.

Support for Mr Biden among older voters — people aged 45 and older — also shot up 13 points from September to 43 per cent. He remains the most popular candidate among voters aged 65 and older, at 39 per cent, while Mr Sanders carries 26 per cent of the vote among voters aged 18-49.

When asked which candidates are best suited to handle six critical issues, a majority of survey respondents picked Mr Biden among four of those issues. He falls short in health care, where Mr Sanders polled at 28 per cent.

But Mr Biden is leading among candidates when it comes to foreign policy (56 per cent) and the economy (38 per cent). He also is matched by Mr Sanders at 26 per cent for addressing the climate crisis; both candidates polled at 19 per cent in June.

Mr Biden's spike arrives as Congress pursues its impeachment probe into President Donald Trump, who asked Ukraine for damaging information on the former vice-president as part of a so-called "quid pro quo" in exchange for security aid. Mr Biden's son Hunter Biden was on the board of a Ukrainian energy company while Mr Biden was serving as vice-president under President Barack Obama.

When it comes to whether the candidates can defeat Mr Trump in 2020, voters surveyed gave the Democratic frontrunners a significant advantage over the president in hypothetical match-ups. Respondents said Mr Biden could win by 10 points at 53 per cent with Mr Trump at 43 per cent, while Mr Sanders tops Mr Trump by nine points (52 per cent to 43 per cent) and Ms Warren by eight points (52 per cent to 44 per cent).

The SSRS survey has a margin of error of plus or minus 3.7 per cent.

The survey results follow Emerson Polling's Tuesday results, which showed Mr Biden in a close race at 27 per cent compared to Mr Sanders at 25 per cent.

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