Former Vice President Joe BidenJoe BidenSupport for impeachment inches up in poll Overnight Defense: Trump's Syria envoy wasn't consulted on withdrawal | McConnell offers resolution urging Trump to rethink Syria | Diplomat says Ukraine aid was tied to political investigations Democrats say they have game changer on impeachment MORE has reached the highest lead over his 2020 Democratic presidential competitors since April, according to a CNN poll released Wednesday.

Biden received 34 percent support from those surveyed that identified as Democratic and Democratic-leaning voters. Behind the former vice president, Sens. Elizabeth WarrenElizabeth Ann WarrenOvernight Health Care — Presented by Partnership for America's Health Care Future — ObamaCare premiums dropping for 2020 | Warren, Buttigieg shift stances on 'Medicare for All' | Drug companies spend big on lobbying Mellman: Trumping peace and prosperity On The Money: Waters clashes with Trump officials over 'disastrous' housing finance plan | Dems jump into Trump turf war over student loans | House passes bill targeting anonymous shell companies MORE (D-Mass.) and Bernie SandersBernie SandersOvernight Health Care — Presented by Partnership for America's Health Care Future — ObamaCare premiums dropping for 2020 | Warren, Buttigieg shift stances on 'Medicare for All' | Drug companies spend big on lobbying Mellman: Trumping peace and prosperity Tlaib to join Sanders at campaign rally in Detroit MORE (I-Vt.) are about neck and neck with 19 percent and 16 percent support, respectively. 

The 15-point lead represents Biden's largest since just after he announced his run on April 25. The former vice president gained support from moderate and conservative Democrats, racial and ethnic minorities and older voters since last month’s poll.

South Bend, Ind., Mayor Pete Buttigieg (D) and Sen. Kamala HarrisKamala Devi HarrisSaagar Enjeti: Warren, Buttigieg don't stand a chance against Trump Warren overtakes Sanders in new poll The Hill's 12:30 Report: Trump faces backlash for comparing impeachment to 'lynching' MORE (D-Calif.) follow behind the front-runners with 6 percent support each. Sen. Amy KlobucharAmy Jean KlobucharHillicon Valley: Zuckerberg would support delaying Libra | More attorneys general join Facebook probe | Defense chief recuses from 'war cloud' contract | Senate GOP blocks two election security bills | FTC brings case against 'stalking' app developer Senate Republicans block two election security bills Warren overtakes Sanders in new poll MORE (D-Minn.) and former Rep. Beto O’Rourke (D-Texas) both received 3 percent of the vote.

Respondents also tabbed the former vice as the best candidate to handle foreign policy, economy, immigration and gun policy. He led Sanders by 3 percentage points as the best candidate to handle health care and ties with the Vermont senator on the climate crisis. 

Biden’s lead in the CNN poll comes as President TrumpDonald John TrumpGraham to introduce resolution condemning House impeachment inquiry Support for impeachment inches up in poll Fox News's Bret Baier calls Trump's attacks on media 'a problem' MORE and Republicans have ramped up attacks against the presidential candidate, specifically regarding his family’s relationship with Ukraine.

A call in which Trump asked Ukrainian President Volodymyr Zelensky to look into the Bidens' interactions in the country is at the center of the House impeachment inquiry against Trump.

There has been no evidence that Biden or his son violated laws in their interactions with Ukraine.

The CNN poll was completed by SSRS from Oct. 17 to 20 surveyed 1,003 adults, including 424 registered voters who identify as or lean Democrat. The margin of error is plus or minus 3.7 percentage points for the overall poll and plus or minus 5.8 percentage points among possible Democratic voters.