WASHINGTON – Young voters cheer Bernie Sanders' anti-establishment message. They turn out in throngs at his rallies. And they form the core of his grassroots efforts to win the Democratic presidential nomination.

But their fiery passion did not translate into the robust turnout he needed on Super Tuesday to win a number of key states, notably in the South where a strong showing by Joe Biden has made the nomination contest a two-person race, especially now that former New York Mayor Michael Bloomberg has dropped out of the race and endorsed Biden.

Exit polls for several states Biden won, including Massachusetts, Texas and several southern states that helped catapult the former vice president into front-runner status, found that while more young voters went to the polls this election cycle, they did not show up at the rate they did in 2016.

At a news conference Wednesday in Vermont, Sanders acknowledged the difficulty of convincing young voters to show up and vote.

"Have we been as successful as I would hope in bringing in young people in? And the answer is 'no'," he said.

"We’re making some progress but historically everybody knows that young people do not vote in the kind of numbers that older people vote," he said. "I think that will change in the general election. But to be honest with you, we have not done as well in bringing young people into the process. It is not easy."

In Virginia, for example, more than 1.3 million voters cast ballots compared to the roughly 800,000 four years ago. But exit polls on Super Tuesday showed that the share of young voters as a percentage of the entire electorate declined in the Old Dominion, diminishing their influence as a voting bloc.

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In addition, the Vermont senator has been grabbing a smaller share of them in most cases.

In Alabama, only 10% of the voters were in the 17-29 range compared to 14% in 2016. Sanders won 46% of those voters Tuesday compared to 40% in 2016.

of the voters were in the 17-29 range compared to 14% in 2016. Sanders won 46% of those voters Tuesday compared to 40% in 2016. In North Carolina, 14% of Tuesday’s electorate were young voters, compared to 16% four years ago. Of those, 57% went for Sanders in 2020 compared to 69% in 2016.

of Tuesday’s electorate were young voters, compared to 16% four years ago. Of those, 57% went for Sanders in 2020 compared to 69% in 2016. In South Carolina which held its primary Saturday, young voters made up 11% of the electorate compared to 15% in 2016. Sanders won 43% of those voters compared to 54% four years ago.

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In Tennessee, 11% of those voters showed up Tuesday versus 15% in 2016. Sanders did better among that group Tuesday winning 63% compared to 61% four years ago.

In Virginia, young voters comprised 13% of Tuesday’s vote compared to 16% in 2016. Sanders won 55% of those voters Tuesday compared with 69% four years ago.

Even Sanders’ home state of Vermont showed a lackluster turnout of young millennials and 'Gen Zers.' Only 11% of the state’s electorate was under 30 compared to 15% when he ran against Clinton, according to exit polls.

And a similar trend played out in other Super Tuesday states such as Texas, where 15% of voters was between 17 and 29 compared to 20% in 2016, and Massachusetts where the share of young voters dropped from 19% four years ago to 16% Tuesday.

The common theme in all those states: Sanders fared worse this year than he did when he faced eventual nominee Hillary Clinton four years ago.

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Sanders’ agenda, which includes erasing student loan debt and providing health care for all, is popular with young people. But the exit polls indicated those voters were not the line of defense they were in 2016.

Sanders’ rallies feature throngs of college students and 20-somethings cheering him on. In Virginia, Sanders held three rallies last week that featured thousands of energized supporters at each stop. On Tuesday, Biden clobbered Sanders in Virginia, winning by 30 percentage points.

Sanders sounded undeterred Tuesday as he promised to keep marching toward the nomination.

"We are going to defeat Trump because we are putting together an unprecedented grass-roots, multi-generational, multi-racial movement," he told supporters at a rally in Vermont.

The lackluster showing is sure to fire up the long-standing assessments of election experts who say young voters’ energy rarely matches their turnout on Election Day. It also undercuts Sanders’ argument that he is best suited to defeat President Donald Trump in November.

Sanders would need an extraordinary turnout among young voters to make up for the loss of moderates who would stay away from the polls if he’s the nominee, according to a study by political scientists David Broockman of the University of California-Berkeley and Joshua Kalla of Yale University, who surveyed some 40,000 voters to assess the electability of the Democratic contenders.

Sanders would need an increase of 11 percentage points among voters between 18 and 29 to offset the loss of swing voters, the study concluded.

But Griffin Schutte, 21, of Virginia Beach, said he switched from Clinton in 2016 to Sanders this year because he thinks the Vermont senator is best to stand up to Trump.

"And I think Bernie Sanders is well equipped to stand by his ideals and his policies that he’s been standing by during his long and very consistent career in politics," Schutte said as he stood in line for a Sanders rally in Richmond Thursday.