Biden maintains 19-point lead over Sanders in new poll

Former vice president Joe BidenJoe BidenWarren: Dershowitz presentation 'nonsensical,' 'could not follow it' Bolton told Barr he was concerned Trump did favors for autocrats: report Dershowitz: Bolton allegations would not constitute impeachable offense MORE leads Sen. Bernie SandersBernie SandersGOP Iowa senator suggests Trump impeachment defense could hurt Biden at caucuses On The Money: Stocks close with steep losses driven by coronavirus fears | Tax season could bring more refund confusion | Trump's new wins for farmers may not undo trade damage Sanders launches first TV ads in Nevada MORE in the latest Hill-HarrisX poll released Monday by 19 points, maintaining a clear separation from the rest of the field in the Democratic presidential primary,

Biden won 35 percent support from Democratic and Democratic-leaning independent registered voters in the June 1-2 survey, compared to 16 percent for Sanders (I-Vt.).

South Bend, Ind. Mayor Pete ButtigiegPeter (Pete) Paul ButtigiegOvernight Energy: Sanders scores highest on green group's voter guide | Trump's latest wins for farmers may not undo trade damage | Amazon employees defy company to speak on climate change Sanders surges to first in New Hampshire: poll Majority sees no ties between business experience and political success MORE was a distant third with 8 percent. He was followed by Sen. Elizabeth WarrenElizabeth Ann WarrenWarren: Dershowitz presentation 'nonsensical,' 'could not follow it' On The Money: Stocks close with steep losses driven by coronavirus fears | Tax season could bring more refund confusion | Trump's new wins for farmers may not undo trade damage Overnight Energy: Sanders scores highest on green group's voter guide | Trump's latest wins for farmers may not undo trade damage | Amazon employees defy company to speak on climate change MORE (D-Mass) at 5 percent.

Sen. Kamala HarrisKamala Devi HarrisBiden leads 2020 pack in congressional endorsements Harris on 2020 endorsement: 'I am not thinking about it right now' Panel: Is Kamala Harris a hypocrite for mulling a Joe Biden endorsement? MORE (D-Calif.) and former Rep. Beto O'RourkeBeto O'RourkeVeronica Escobar to give Spanish-language response to Trump State of the Union address Biden calls for revoking key online legal protection Trump mocks Booker over suspended presidential campaign MORE were supported by 4 percent of respondents while Sen. Cory BookerCory Anthony BookerSenate Dems to Pompeo: Comments about NPR reporter 'insulting and contemptuous' Black caucus in Nevada: 'Notion that Biden has all of black vote is not true' The Hill's 12:30 Report: House managers to begin opening arguments on day two MORE (D-N.J.) was named by 3 percent.

All of the other Democratic candidates were named by 1 percent or fewer survey participants. Seventeen percent of respondents said they were unsure about their preference.

The results overall are largely similar to a May 17-18 Hill-HarrisX survey which also found Biden with a 19 percent lead over his Vermont-based rival. The former vice president received 33 percent support in the earlier poll while Sanders received 14 percent.

The May survey showed Warren in third place with 8 percent support and Buttigieg in fourth with 6 percent. The shift between the two candidates' support within the polls is within the surveys' sampling margins of error.

The newer poll found Biden as the top named candidate of both men and women and also across all age groups, although his lead over Sanders among voters between 18 and 34 was just one point, indicating a statistical tie. Older voters were overwhelmingly more likely to prefer the former vice president to other candidates with 47 percent of respondents 50 years old and older supporting him.

Among white voters, Biden was the preferred candidate while Sanders and Buttigieg were essentially tied for second-place. Biden enjoyed an even stronger lead among black respondents while Sanders showed strength among Hispanics although the sample size for both groups is too small to state this definitively.

Since Biden's entry into the presidential contest in April, the race has become relatively stable with no candidate able to dislodge Sanders from second-place and Biden from first, although that may change following the first debate contest which will be hosted by the Democratic National Committee June 26 and 27.

Presidential aspirants sharpened their messages over the weekend at the California Democratic Party's annual convention in San Francisco where several candidates called for impeaching President TrumpDonald John TrumpWarren: Dershowitz presentation 'nonsensical,' 'could not follow it' Bolton told Barr he was concerned Trump did favors for autocrats: report Dershowitz: Bolton allegations would not constitute impeachable offense MORE. Former Colorado Gov. John HickenlooperJohn HickenlooperFor a healthy aging workforce policy, look to Colorado Mitch McConnell may win the impeachment and lose the Senate Hickenlooper raised .8 million for Colorado Senate bid in fourth quarter of 2019 MORE was booed by attendees after he expressed skepticism about a proposed Green New Deal environmental initiative and proposals to have the federal government administer medical insurance for all Americans.

Warren and Buttigieg took veiled swipes at Biden at the event with the Massachusetts senator implicitly denouncing his recent declarations that Republicans would become more inclined toward bipartisanship if President Trump is defeated in 2020. Buttigieg said that Democrats needed "a new generation of leaders," a reference to Biden's age of 76 years.

Sanders indirectly slammed Biden for skipping the event and argued that the party would not be able to defeat Trump unless it embraced a progressive agenda.

The latest Hill-HarrisX survey was conducted June 1-2 among a statistically representative sample of 1,001 registered voters. The question about 2020 Democratic presidential preference was asked of a subset of 431 respondents who said they were Democrats or independents who leaned toward the Democratic Party.

The larger survey has a 3.1 percent sampling margin of error and a 95 percent confidence level. The subset has a sampling margin of error of 4.7 percentage points.

—Matthew Sheffield