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

Former Vice President Joe BidenJoe BidenBiden evokes 1968, asks voters to imagine if Obama had been assassinated Biden blasts Trump's 'embarrassing' actions heading into G-7 summit Steyer calls on DNC to expand polling criteria for debates MORE's support jumped 5 points, slightly extending his lead over Sen. Bernie SandersBernie SandersHickenlooper day-old Senate bid faces pushback from progressives Steyer calls on DNC to expand polling criteria for debates Andrew Yang: News coverage of Trump a 'microcosm' of issues facing country 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 Ann WarrenSteyer calls on DNC to expand polling criteria for debates Gabbard hits DNC over poll criteria for debates The Hill's Campaign Report: Democratic field begins to shrink ahead of critical stretch 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 Devi HarrisSteyer calls on DNC to expand polling criteria for debates Gabbard hits DNC over poll criteria for debates The Hill's Campaign Report: Democratic field begins to shrink ahead of critical stretch 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 ButtigiegPeter (Pete) Paul ButtigiegSteyer calls on DNC to expand polling criteria for debates The Hill's 12:30 Report: Stocks sink as Trump fights with Fed, China Gabbard hits DNC over poll criteria for debates 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