Biden extends lead; Sanders, Warren see support grow in new poll

Former Vice President Joe BidenJoe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE's support jumped 5 points, slightly extending his lead over Sen. Bernie SandersBernie SandersSirota reacts to report of harassment, doxing by Harris supporters Republicans not immune to the malady that hobbled Democrats The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election MORE (I-Vt.) in the latest Hill-HarrisX poll. 

The survey showed that 34 percent of likely Democratic primary voters back Biden, marking a 14-point lead over Sanders.

It also found rising support for Sanders and Sen. Elizabeth WarrenElizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.), the only other two candidates in double figures in the poll.

Sanders jumped by 4 percent to 20 percent and Warren by 3 percent to 12 percent.

Sen. Kamala HarrisKamala HarrisTexas Democratic official urges Biden to visit state: 'I thought he had his own plane' The Hill's Campaign Report: Biden on Trump: 'He'll leave' l GOP laywers brush off Trump's election remarks l Obama's endorsements A game theorist's advice to President Trump on filling the Supreme Court seat MORE (D-Calif.) is in fourth place with 9 percent support, but her numbers have dropped by 2 percent since the last poll conducted two weeks ago. South Bend, Ind., Mayor Pete ButtigiegPete ButtigiegBillionaire who donated to Trump in 2016 donates to Biden The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November Buttigieg stands in as Pence for Harris's debate practice MORE rounded out the top five with 5 percent, a 4 percent jump over two weeks. 

Former Rep. Beto O’Rourke (D-Texas), meanwhile, dropped to sixth place with 4 percent support.

The new poll also suggests that a growing number of Democratic voters are starting to make up their minds about which candidate to back.

The survey showed that the number of undecided voters dropped to 8 percent from 17 percent.

The latest poll can be viewed as welcome news for Sanders, Biden and Warren going into the second round of primary debates. Earlier this month, Biden’s support slipped below 30 percent, his lowest mark in the Hill-HarrisX survey to date.

The Democrats are poised to face-off again in two debates this week in Detroit.

Warren and Sanders are set to headline the first of debates on Tuesday, while Biden will take center stage along with Harris the following night.

This marks the first time Warren and Sanders will have shared the debate stage. Both liberal heavyweights have largely avoided criticizing each other but could look to set themselves apart as the top progressive candidate. 

The lineup also marks a potential rematch for Biden and Harris, who clashed during the last debate over civil rights issues. 

Leading up to the debate, Harris unveiled her health care plan, which seeks to expand coverage without getting rid of private insurance.

The plan has already drawn fire from both Sanders and Biden alike.

While Biden accused Harris of backtracking on her pledge to support “Medicare fo All,” Sanders slammed the plan for what he characterized as relying too heavily on private insurance. 

The Hill-HarrisX survey was conducted online among 1,000 registered voters. The sampling margin of error is plus or minus 3.1 percentage points.

—Tess Bonn