Almost 30 percent of Biden supporters pick Sanders as second choice

Former Vice President Joe BidenJoe BidenLawmakers, activists remember civil rights icons to mark 'Bloody Sunday' Fauci predicts high schoolers will receive coronavirus vaccinations this fall Biden nominates female generals whose promotions were reportedly delayed under Trump MORE (D) is atop the field of Democratic presidential candidates in most polls, but a new survey finds that many of his supporters would be willing to back his top rival, Sen. Bernie SandersBernie SandersLawmakers, activists remember civil rights icons to mark 'Bloody Sunday' Progressives' majority delusions politically costly Sinema pushes back on criticism of her vote against minimum wage MORE (I-Vt.).

A Hill-HarrisX poll released Wednesday found that 27 percent of registered voters who support Biden said Sanders was their second pick to become the Democratic nominee.

He was followed by Sen. Kamala HarrisKamala HarrisWhite House says Biden would prefer to not end filibuster Biden takes victory lap after Senate passes coronavirus relief package It will be Vice (or) President Harris against Gov. DeSantis in 2024 — bet on it MORE (D-Calif.), with 15 percent of Biden backers saying she was their second choice. Former Rep. Beto O'RourkeBeto O'RourkeTexas Republican criticizes Cruz for Cancun trip: 'When a crisis hits my state, I'm there' Progressives target 'Cancun Cruz' in ad to run on 147 Texas radio stations 'Get off TV': Critics blast Abbott over handling of Texas power outages following winter storm MORE (D-Texas) garnered 11 percent and South Bend, Ind., Mayor Pete ButtigiegPete ButtigiegThe Hill's 12:30 Report - Presented by ExxonMobil - Senate begins marathon vote-a-rama before .9T COVID-19 relief passage The Hill's Morning Report - Presented by Facebook - Virus relief bill headed for weekend vote Biden turns focus to next priority with infrastructure talks MORE (D) received 10 percent.

In the single digits were Sen. Elizabeth WarrenElizabeth WarrenSenate rejects Sanders minimum wage hike Philly city council calls on Biden to 'cancel all student loan debt' in first 100 days Hillicon Valley: High alert as new QAnon date approaches Thursday | Biden signals another reversal from Trump with national security guidance | Parler files a new case MORE (D-Mass.), at 8 percent; Sen. Kirsten GillibrandKirsten GillibrandABC names new deputy political director, weekend White House correspondent The Hill's Morning Report - Presented by Facebook - Lawmakers face Capitol threat as senators line up votes for relief bill The Hill's Morning Report - Presented by Facebook - Senate Dems face unity test; Tanden nomination falls MORE (D-N.Y.), with 7 percent; and Sen. Cory BookerCory Booker'Bloody Sunday' to be commemorated for first time without John Lewis It's in America's best interest to lead global COVID-19 vaccine distribution ABC names new deputy political director, weekend White House correspondent MORE (D-N.J.), at 6 percent.

Other polls have seen similar results.

An April 29-May 5 survey of 15,770 likely Democratic primary voters conducted by Morning Consult found that 31 percent of Biden supporters said Sanders was their backup choice. Harris was named by 13 percent, followed by Warren's 10 percent.

Before Biden entered the race, an April 12-15 poll from Change Research, a left-leaning group, found that Sanders gained 6 percentage points of support when the former vice president was excluded from the questionnaire seen by respondents. O'Rourke gained 5 points, while Buttigieg saw a 4-point increase.

An April 11-15 survey conducted by Monmouth University found that Sanders gained 7 points without Biden, with Harris and Warren each gaining 3 points.

The level of support among Biden backers for the further-left Sanders suggests Democratic voters don't neatly align in discrete demographic or ideological "lanes," Ruy Teixeira, a senior fellow at the Center for American Progress Action Fund, said Wednesday on Hill.TV's "What America's Thinking."

"The whole business with lanes can be quite exaggerated, particularly if we're thinking about the actual voters as opposed to the people analyzing the voters," he told host Jamal Simmons. "They have a more broad, more disparate sense of preferences, and the electability thing sort of gets plugged in there for a lot of Democrats who are sick of Trump."

To the extent that discrete groupings exist among dedicated party activists or large donors, the challenge for candidates seeking to dislodge Biden is to find a way to expand their appeal beyond their initial constituencies, Teixeira said.

"What you want to do is attract people across these so-called lanes," he said. "That's why Biden's doing so well at this point: He's taking people from all the lanes."

But expanding their support base may prove difficult with more than 20 contenders in the race, Republican pollster Ed Goeas told Simmons.

"American voters like to choose between two candidates," the veteran GOP strategist said.

"That is the one complicating factor you have now with Sanders and Biden both very high on name ID; they may be crowding out the second choice and certainly the data shows that's what's happening," Goeas said.

The Hill-HarrisX survey was conducted May 3-4 among 440 Democratic and independent voters who leaned toward the Democratic Party. The survey has a 95 percent confidence level and a 4.7 percent sampling margin of error.

The second choice analysis is based on a subset of 203 respondents who said Biden was their first choice. The sampling margin of error for the subset is 6.9 percent.

—Matthew Sheffield