The independent Field Poll said that by a narrow margin, more voters said unions do more harm than good, as opposed to those who see organized labor as generally beneficial.
The slide in support represents a turnaround from a 2011 Field survey, when more voters said unions resulted in more good than harm.
The shift comes at a time of ongoing labor conflicts in the state and nation, often involving government employee pensions and retirement benefits.
In the San Francisco Bay Area, two transit strikes this year caused headaches for hundreds of thousands of commuters. Retirement costs for government workers contributed to bankruptcies in three California cities in recent years — Stockton, Vallejo and San Bernardino.
The cost of “public pensions are starting to crowd out the services that local governments can provide. That doesn’t sit well with the public,” pollster Mark DiCamillo said.
Compared to the earlier poll, unions lost ground across most age, political and demographic groups.
Since 2011 “virtually every voter subgroup now displays a shift toward a somewhat more negative view of labor unions than they had expressed previously,” the survey found.
The poll of 1,002 registered voters, conducted Nov. 14 to Dec. 5, found that 45 percent said labor unions do “more harm than good.”
That compared to 40 percent who said unions do “more good than harm.”
The findings were nearly identical when voters were asked about labor unions, generally, or public employee unions.
Those viewing unions more negatively increased 10 percentage points from March 2011, while the percentage of those viewing unions as more beneficial dropped 6 points during the period, the survey said.
The Democratic Party has long had close ties to unions, but the survey found 30 percent of registered Democrats now say unions do more harm than good, up from 21 percent in the 2011 survey.
More than half of whites, 51 percent, say unions do more harm than good, up from 39 percent in 2011. Even in households with a union member, 31 percent said unions do more harm than good, up from 18 percent in 2011.
Several California mayors want voters to consider an initiative on next year’s ballot that would amend the state Constitution to allow local governments to negotiate changes in pension benefits for current and future employees.
Last year, labor groups and other Democratic interests funneled at least $75 million into their drive to defeat Proposition 32, which would have starved unions of the tens of millions of dollars they use to finance campaigns and political organizing.
The survey had a margin of error of plus or minus 3.2 percentage points.