Presumptive Democratic presidential nominee Hillary Clinton beat Bernie Sanders Tuesday by 13 percentage points in California, the latest numbers from last week's primary election show.
That gap is likely to shrink somewhat when all ballots are counted, but still many are wondering why the historic surge in voter registrations leading up to the election, driven in large measure by young people, failed to result in a win or closer race for Sanders.
“It definitely wasn’t the turnout that I was hoping for," said Sebastian Ventling, a 28-year-old Sanders pledged delegate who helped organize supporters in Santa Clarita. "I’m pretty disappointed with the actual results. We were hoping for a victory obviously or even for a narrow tie."
In the final 45 days before the May 23 voter registration deadline, close to 650,000 voter registrations were added to the state total, according to the Secretary of State Alex Padilla.
As of June 3, 17,915,053 Californians were registered to vote — about 760,000 more than similar tallies for the 2012 presidential primary.
The increase was aided in part by Facebook, according to the Secretary of State's office, which targeted California residents on the social media site and encouraged them to register to vote.
"That is the largest voter surge the state's ever seen, period — larger than we saw during any general election or primary election," said Paul Mitchell, vice president of Political Data, the bipartisan voter data company.
Mitchell believes the surge in registrations could have led to some issues with pre-primary polls. Heading into Tuesday, the respected Field Poll and Public Policy Institute of California poll showed Clinton and Sanders nearly neck-and-neck.
"If your voter sample is skewed a little bit too much toward voters who are ultimately not going to vote, it can have a negative effect on the findings of the overall poll," Mitchell said. "I think it's possible that pollsters were persuaded by this big voter surge."
It won't be possible to know how many young people turned out to vote until all of the ballots are tallied, which will take a few weeks. Counties have until July 8 to submit their results to the state and the state has until July 15 to certify the statewide results.
It may turn out that other factors besides light turnout among young voters weighed more heavily in Clinton's win: a deep grassroots campaign informed by her 2008 victory here in the presidential primary; strong support for her in Latino and black communities; and backing by higher propensity voters who are often older.
But Mitchell worked on an exit survey with the online site Capitol Weekly of early mail-in ballots that provides a few clues. In that survey, Mitchell found young people were participating at surprisingly low levels.
"Essentially you had this population that was half of the surge or more and only 10 percent of the people had actually mailed in their ballots," he said.
Young voters could have registered at high numbers in reaction to events happening nationally in the presidential campaign, according to Mitchell. But their enthusiasm may not have translated into actual votes. Understanding ballot measures and how to vote in congressional races may have also deterred some people, he said.
"This kind of immediate excitement and motivation to vote and register was not necessarily matched when they got to kind of the more mundane parts of voting and finding a stamp and so on," he said.
Ventling, the Sanders supporter, said one challenge in ensuring that young voters cast ballots is that many are new voters and unfamiliar with the rules of voting. He said he was disheartened when friends reached out to him Tuesday wanting to vote for Sanders, only to discover they weren't registered and couldn't cast a ballot.
“We’ve got to keep making it easier,” he said. “It kept a lot of people out."
Those who failed to register for the primary by California's May 23 deadline would have been locked out, though they still have time to register for the November general election. Election officials plan to implement same-day registration in 2017.
It wouldn't be a new phenomenon if it turns out large numbers of young voters failed to vote in Tuesday's primary in the numbers their registration activity suggested. Young voters have historically been underrepresented among likely voters.
The Public Policy Institute of California's research shows those between 18 and 34 make up 33 percent of the state’s adult population, but represent just 18 percent of likely voters.