By Chris Kahn

NEW YORK, June 12 (Reuters) - Bernie Sanders may have lost his bid to become the Democratic nominee for the White House, but party members don't want the U.S. senator from Vermont to step off the stage.

More than three-quarters of Democrats say Sanders should have a "major role" in shaping the party's positions, while nearly two thirds say Hillary Clinton - who beat him for the nomination - should pick him as her vice-presidential running mate, according to a Reuters/Ipsos poll.

SEE ALSO: Poll: Clinton leads Trump by 11 points in White House race

In a sign that Democrats hope their party can unite after a fierce primary season, two-thirds also said that Sanders should endorse Clinton, a former secretary of state and senator who appears bound for a showdown with Republican Donald Trump in November's presidential election.

Sanders, a self-described Democratic socialist, managed to turn his long-shot run into a mass movement with hard-line proposals to combat wealth inequality, increase access to health care and education, and defend the environment.

His challenge to Clinton, one of the best-known figures in American politics, lasted far longer than expected, as he racked up strong results in a number of state nominating contests and stayed in the race even when the delegate count seemed to spell his doom, and yielded record numbers of small donations to his campaign.

Hillary Clinton and Bernie Sanders:

15 PHOTOS Hillary Clinton and Bernie Sanders at Las Vegas town hall See Gallery Poll: U.S. Democrats want 'major role' for Sanders Democratic presidential candidate Hillary Clinton speaks during in a televised town hall meeting with Senator Bernie Sanders at the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas on February 18, 2016. The town hall discussion focused on issues affecting Nevada and the Latino Community was held just two days before Nevadas First in the West presidential caucus onÂ Saturday, February 20, 2016. / AFP / JOHN GURZINSKI (Photo credit should read JOHN GURZINSKI/AFP/Getty Images) MSNBC - ELECTION COVERAGE -- MSNBC and Telemundo Clinton-Sanders Town Hall -- Pictured: Fmr. Secretary of State Hillary Clinton appears during the 'MSNBC and Telemundo Clinton-Sanders Town Hall' on Thursday, February 18, 2016 at the KMA Event Center in Las Vegas -- (Photo by: Virginia Sherwood/MSNBC/NBCU Photo Bank via Getty Images) MSNBC - ELECTION COVERAGE -- MSNBC and Telemundo Clinton-Sanders Town Hall -- Pictured: Chuck Todd appears during the 'MSNBC and Telemundo Clinton-Sanders Town Hall' on Thursday, February 18, 2016 at the KMA Event Center in Las Vegas -- (Photo by: Virginia Sherwood/MSNBC/NBCU Photo Bank via Getty Images) Democratic presidential candidate Senator Bernie Sanders speaks during in a televised town hall meeting with Hillary Clinton at the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas on February 18, 2016. The town hall discussion focused on issues affecting Nevada and the Latino Community was held just two days before Nevadas First in the West presidential caucus onÂ Saturday, February 20, 2016. / AFP / JOHN GURZINSKI (Photo credit should read JOHN GURZINSKI/AFP/Getty Images) Democratic presidential candidate Hillary Clinton speaks during in a televised town hall meeting with Senator Bernie Sanders at the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas on February 18, 2016. The town hall discussion focused on issues affecting Nevada and the Latino Community was held just two days before Nevadas First in the West presidential caucus onÂ Saturday, February 20, 2016. / AFP / JOHN GURZINSKI (Photo credit should read JOHN GURZINSKI/AFP/Getty Images) MSNBC - ELECTION COVERAGE -- MSNBC and Telemundo Clinton-Sanders Town Hall -- Pictured: Vermont Sen. Bernie Sanders appears during the 'MSNBC and Telemundo Clinton-Sanders Town Hall' on Thursday, February 18, 2016 at the KMA Event Center in Las Vegas -- (Photo by: Virginia Sherwood/MSNBC/NBCU Photo Bank via Getty Images) Democratic presidential candidate Senator Bernie Sanders speaks during in a televised town hall meeting with Hillary Clinton at the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas on February 18, 2016. The town hall discussion focused on issues affecting Nevada and the Latino Community was held just two days before Nevadas First in the West presidential caucus onÂ Saturday, February 20, 2016. / AFP / JOHN GURZINSKI (Photo credit should read JOHN GURZINSKI/AFP/Getty Images) MSNBC - ELECTION COVERAGE -- MSNBC and Telemundo Clinton-Sanders Town Hall -- Pictured: Fmr. Secretary of State Hillary Clinton appears during the 'MSNBC and Telemundo Clinton-Sanders Town Hall' on Thursday, February 18, 2016 at the KMA Event Center in Las Vegas -- (Photo by: Virginia Sherwood/MSNBC/NBCU Photo Bank via Getty Images) Democratic presidential candidate Hillary Clinton speaks during in a televised town hall meeting with Senator Bernie Sanders at the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas on February 18, 2016. The town hall discussion focused on issues affecting Nevada and the Latino Community was held just two days before Nevadas First in the West presidential caucus onÂ Saturday, February 20, 2016. / AFP / JOHN GURZINSKI (Photo credit should read JOHN GURZINSKI/AFP/Getty Images) MSNBC - ELECTION COVERAGE -- MSNBC and Telemundo Clinton-Sanders Town Hall -- Pictured: Fmr. Secretary of State Hillary Clinton appears during the 'MSNBC and Telemundo Clinton-Sanders Town Hall' on Thursday, February 18, 2016 at the KMA Event Center in Las Vegas -- (Photo by: Virginia Sherwood/MSNBC/NBCU Photo Bank via Getty Images) MSNBC - ELECTION COVERAGE -- MSNBC and Telemundo Clinton-Sanders Town Hall -- Pictured: Vermont Sen. Bernie Sanders appears during the 'MSNBC and Telemundo Clinton-Sanders Town Hall' on Thursday, February 18, 2016 at the KMA Event Center in Las Vegas -- (Photo by: Virginia Sherwood/MSNBC/NBCU Photo Bank via Getty Images) Democratic presidential candidate Senator Bernie Sanders speaks during in a televised town hall meeting with Hillary Clinton at the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas on February 18, 2016. The town hall discussion focused on issues affecting Nevada and the Latino Community was held just two days before Nevadas First in the West presidential caucus onÂ Saturday, February 20, 2016. / AFP / JOHN GURZINSKI (Photo credit should read JOHN GURZINSKI/AFP/Getty Images) Democratic presidential candidate Hillary Clinton speaks during in a televised town hall meeting with Senator Bernie Sanders at the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas on February 18, 2016. The town hall discussion focused on issues affecting Nevada and the Latino Community was held just two days before Nevadas First in the West presidential caucus onÂ Saturday, February 20, 2016. / AFP / JOHN GURZINSKI (Photo credit should read JOHN GURZINSKI/AFP/Getty Images) MSNBC - ELECTION COVERAGE -- MSNBC and Telemundo Clinton-Sanders Town Hall -- Pictured: JosÃ© DÃ­az-Balart appears during the 'MSNBC and Telemundo Clinton-Sanders Town Hall' on Thursday, February 18, 2016 at the KMA Event Center in Las Vegas -- (Photo by: Virginia Sherwood/MSNBC/NBCU Photo Bank via Getty Images) MSNBC - ELECTION COVERAGE -- MSNBC and Telemundo Clinton-Sanders Town Hall -- Pictured: Vermont Sen. Bernie Sanders appears during the 'MSNBC and Telemundo Clinton-Sanders Town Hall' on Thursday, February 18, 2016 at the KMA Event Center in Las Vegas -- (Photo by: Virginia Sherwood/MSNBC/NBCU Photo Bank via Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Sanders so far has not conceded defeat, even though Clinton recently clinched the nomination and won endorsements from President Barack Obama and U.S. Senator Elizabeth Warren of Massachusetts - a favorite of the same left-leaning voters who supported him.

Sanders has said he will continue to push for a liberal agenda heading into the Democratic National Convention in July - when Clinton's nomination is expected to become official - though he has hinted he does not want his presence to hurt the Democrats' chances of keeping the White House.

"We will not let Donald Trump become president," Sanders told supporters last week.

The poll, conducted June 7-10 - right after Clinton sewed up the delegate majority to become the presumptive Democratic nominee - showed that while most Democrats want Sanders to line up behind Clinton, about 44 percent would like him to make an independent run for the White House. Some 47 percent said he should not.

The poll included 455 respondents and has a credibility interval, a measure of accuracy, of 5.3 percentage points.

(Editing by Richard Valdmanis and Leslie Adler)