Hillary Clinton holds a lopsided lead over Donald Trump in decidedly Democratic California, but weaknesses here with younger voters suggest problems that could thwart her campaign in more contested states, a new poll has found.

Trump once vowed to win California and other heavily Democratic states, but he hasn’t said that recently, and the poll shows why: Clinton led Trump by 25 points, 58% to 33%, when the two candidates were matched head to head in the latest USC Dornsife/Los Angeles Times poll of registered voters.

When the choices were expanded to include Libertarian nominee Gary Johnson and Green Party nominee Jill Stein, Clinton lost more support than Trump, and the gap between the two narrowed to 20 points. Johnson picked up 11% and Stein 6%.

Even at 49% to 29%, that is still a substantial Clinton lead over Trump — just below the historic margins achieved by President Obama in his California victories in 2008 and 2012. But it nonetheless demonstrated limits to Clinton’s hold on some voters, particularly young ones who formed a key part of Obama’s success.


“In a state that is more closely contested than California, the Johnson and Stein candidacies have a potential to cause a problem for Clinton,” said poll director Dan Schnur, who heads USC’s Jesse M. Unruh Institute of Politics. “Out here, it’s probably not going to make a difference.”

Trump appears to have no shot at moving California and its 55 electoral votes into contested territory. Indeed, he creates a significant drag on Republicans down the ballot here.

In every part of the state, voters said they would be less inclined to side with a congressional candidate who had endorsed Trump; statewide, 40% said they would be less likely to vote for such a candidate, and 15% said they would be more likely.

That could represent a problem for some GOP congressional candidates in the state, particularly given the likelihood of a tepid Republican turnout. Not only is the presidential race not close here, the two candidates for Senate on the November ballot are both Democrats, reducing the draw for Republican voters.


A candidate’s endorsement of Clinton was a wash, the poll found, with about equal numbers of voters saying they would be more or less likely to vote for a candidate who had backed her.

The poll was conducted Sept. 1 to 8 online by SurveyMonkey for the USC Dornsife College of Letters, Arts and Sciences and The Times. It is the third statewide SurveyMonkey poll that USC and The Times have commissioned as the organizations continue to experiment with methods for measuring public opinion.

The poll questioned 4,212 people who said they were registered to vote in California. The error estimate was 2 points in either direction for all respondents, larger for subgroups.


How the poll was conducted »

The poll showed Clinton winning in almost every area of the state, even those typically taken by Republicans.

And she also was winning a group among whom she has trailed nationally and in 2016’s most competitive states: those without a college education. That is because in California many of those voters are nonwhite, a chunk of the electorate on which Clinton maintains a fierce grasp.


In the two way matchup against Trump, Clinton was winning almost 8 in 10 African American voters, about three-quarters of Latino voters and 69% of Asian voters. Among white voters, she did not quite achieve a majority, but at 49% to 43% maintained a 6-point edge.

It was the views of young voters, many of whom sided with Clinton’s opponent, Sen. Bernie Sanders, in the state’s June primary, that were most striking and an indicator of potential trouble for the Democrat elsewhere.

Among those ages 18 to 24, Clinton won 71% against Trump in the two-way matchup, but only 45% when all four candidates were listed. Among those ages 25 to 34, Clinton’s support dropped from 67% to 54%.

Trump’s support change relatively little: He won 24% of the youngest voters against Clinton in the two-way contest and lost only 5 points when the other candidates were included. Among those ages 25-34, he went from 22% to 14%.


Trump came in third among voters younger than 25, behind Johnson with 21% although the gap is well within the poll’s margin of error for the relatively small subgroup of young voters. Stein was at 12%. Among those ages 25 to 34, Trump was again in third, while Johnson received 17% of the vote and Stein 10%.

The results suggest that among younger voters, Clinton is acceptable when she is the only alternative to Trump; when there are other options, some voters are not as keen on her.

Results could differ in battleground states where young voters are being more eagerly courted by the Clinton campaign. Some former Sanders backers in California have said they feel free to vote for one of the alternative candidates, secure in the belief that Trump won’t win the state regardless of their votes.

It is also unclear whether backing for Johnson and Stein will hold until election day, because support for minor-party candidates typically ebbs as November nears. In this case, however, both Clinton and Trump conjure strongly negative impressions among many voters that may make alternatives more palatable.


Voters younger than 35 — who make up nearly 1 in 3 casting ballots — were also far less likely to say they were drawn to vote by the presidential election, compared with other age groups.

Among all voters, 56% said the presidential race was the biggest draw in November. But among those younger than 25, only 41% said they were most enthusiastic about voting in the presidential election. Among those ages 25 to 34, only 36% cited the presidential contest.

Both sets of younger voters were far more likely than older Californians to cite as a prime November interest the measure that would legalize personal use of marijuana.


Younger voters have been a persistent thorn in Clinton’s side. They are strongly Democratic in their voting patterns and disagree with Trump’s views on social, economic and military issues.

But they also have been among those most critical of Clinton when it comes to honesty and ethics, and many have criticized her policy positions as insufficiently liberal.

The fact that support for her dropped significantly when Johnson and Stein were added as options “does not bode well” for the odds they will turn out in strong numbers for Clinton, said Jon Cohen, chief research officer for SurveyMonkey.

For more on politics »


Despite that concern, Clinton’s overall standing in California remains secure.

In the head-to-head matchup, she enjoyed a 35-point margin over Trump among female voters and was 13 points ahead of the Republican among men, a group that often sides with him elsewhere. Among voters ages 65 and older — another group aligned with Trump in national and swing state polls — Clinton was 2 points ahead.

In the state’s Democratic centers, the Bay Area and Greater Los Angeles, she was leading by 48 and 41 points respectively.

But even in places normally sympathetic to Republican candidates, Clinton was ahead: by 10 points in the Central Valley and 7 points in the Orange County and San Diego area.


The only geographic area in which she trailed was the Inland Empire. There, where the 2008 economic collapse hit hard and where the share of white voters without college educations is higher than in coastal regions, Trump was leading by 8 points.

The difference between California and other states involves both its more liberal ideology and its demographics. Trump is suffering from the same factors that have made the state impossible for Republican nominees to overcome since George H.W. Bush eked out a narrow victory in 1988 when the state was more racially homogenous.

Trump’s success this year has been greatest in areas where white voters are dominant, but in California 44% of voters now are nonwhite.

Trump maintained his advantage in California among whites without college degrees, leading Clinton by 13 points. Clinton led him by 29 points among college-educated whites.


Whether they hold college degrees or not, about 8 in 10 African American voters sided with Clinton. The same was true among Latino voters, at least 7 in 10 of whom sided with her no matter the education level. Those numbers did not shift markedly when the two minor-party candidates were added to the race.

The influence of nonwhite voters here also explains much of the trouble facing the down-ballot candidates who endorsed Trump.

“The greatest resistance to Trump’s candidacy comes from minority voters,” Schnur said. “There are a lot more minority voters in California than in most states, so it’s not surprising his numbers here are so much worse.”

cathleen.decker@latimes.com


Twitter: @cathleendecker

ALSO:

Coasting is no longer an option for Hillary Clinton, given Donald Trump’s resilience

In Pennsylvania and nationally, Trump’s problems with suburban voters blunt his ascent


‘I’m just lost.’ Voters find it hard to commit to Clinton or Trump

Donald Trump says the U.S. should have taken Iraq’s oil. Here’s why that wasn’t an option

Updates on California politics

Live coverage from the campaign trail