Clinton and Sanders Neck and Neck in California Poll

As state election officials report surging voter interest in the June 7 primary, a new poll from the Public Policy Institute of California shows that Vermont Sen. Bernie Sanders has closed the gap against Hillary Clinton in the race for the Democratic nomination.

Among likely voters in the Democratic primary, the PPIC poll shows Clinton and Sanders essentially tied in California, with Clinton winning 46 percent support to 44 percent for Sanders. That’s within the poll’s margin of error.

"This is clearly bad news for Hillary Clinton," said UC San Diego political science professor Thad Kousser.

"Even now that she's functionally clinched the Democratic nomination for president, she still doesn't have Democratic voters solidifying behind her," Kousser added.

Clinton does best among Latinos and voters who are 45 and older. Sanders has the edge with younger voters and independent voters who have no party preference.

PPIC president and survey director Mark Baldassare says those nonpartisans are the voters who will likely determine the outcome of the June 7 primary.

"Independent voters can be the difference makers in the Democratic presidential primary in ways that independent voters in other states have been the difference makers in the Republican presidential primaries,” says Baldassare.

There's a catch, though. While nonpartisans can vote in the Democratic primary, they have to ask for a Democratic ballot by mailing in a request to their local elections office or exchanging their ballot without the Democratic presidential candidates at their polling place on Election Day.

In hypothetical head-to-head fall matchups, both Clinton and Sanders lead likely Republican nominee Donald Trump. Clinton leads Trump by 10 points, 49 to 39 percent. Sanders does even better, besting Trump by 17 points, 53 to 36 percent.

Meanwhile, in the relatively sleepy U.S. Senate race, Democrats Kamala Harris and Loretta Sanchez appear headed for a fall matchup. Attorney General Harris leads congresswoman Sanchez 27 to 19 percent. Three Republicans running are all below 10 percent, while 31 percent of voters say they’re still undecided.

That race is far from decided. But if Harris and Sanchez finish one-two on June 7 as expected, the fall runoff will be fascinating. The PPIC poll shows Harris leading Sanchez 34 to 26 percent. Among likely voters in the June primary, 24 percent said they wouldn’t bother voting if the Senate race comes down to two Democrats.

On Tuesday, Secretary of State Alex Padilla reported 1.8 million voter registrations or registration updates (such as political change of party or address) took place on the online voter registration website since Jan. 1.

Padilla calls the lead-up to the midnight Monday deadline “the most online registration activity this year, and the second-highest total in the nearly four-year history of the online registration site."

The secretary of state’s office said Californians 25 and younger accounted for 42 percent of the voter registration activity. Assuming they follow through and cast ballots in the Democratic primary, it could provide a boost to Bernie Sanders, who does best among younger voters.

Paul Mitchell, who crunches voter data and sells the analysis to campaigns, notes the registration surge has benefited the California Democratic Party far more than the GOP.

No question all this interest in voting is great for democracy. But some worry that local election officials aren’t prepared for the onslaught of ballots likely to arrive on or before Election Day.

"If this is your first time voting, this is a tough time to make your entry into the voting process," says Kim Alexander of the California Voter Foundation.

Referring to who can and cannot vote in the Republican and Democratic presidential primaries, Alexander notes that “we have really confusing primary participation rules.”

Only registered Republicans can vote for Donald Trump or one of the other Republicans on the presidential ballot. The state Democratic Party allows voters with “no party preference” to cast ballots for Clinton or Sanders, but only if they specifically request a Democratic ballot.

But analyst Mitchell says it appears most nonpartisan voters aren’t doing that.

"In Los Angeles County 91 percent of the ballots mailed to nonpartisan voters had no presidential candidates on it,” says Mitchell. “And 85 percent of ballots sent statewide to nonpartisan or independent voters have no presidential candidates on it.”

Both Mitchell and Alexander made their comments earlier this week on KQED's Forum program.

There’s still time for independent voters to request a Democratic ballot, and they can even do that at their polling place on Election Day. Still, the data suggest a lot of confusion out there with little time to fix it.

California's secretary of state maintains a voter information hotline at 800-345-VOTE (8683) to answer questions.

This story is part of California Counts, a collaboration of KPBS, KPCC, KQED and Capital Public Radio to report on the 2016 election. The coverage focuses on major issues and solicits diverse voices on what’s important to the future of California.

Copyright KQED 2016. Read more in this series and let us know your thoughts on Twitter using the hashtag #CACounts.