For years, even decades, polling has consistently found that Californians’ highest political priority is public education.

That trend continues in a new survey by the Public Policy Institute of California, conducted in the wake of teacher strikes for higher salaries in three urban school districts.

PPIC found that three-quarters of California adults and likely voters want Gov. Gavin Newsom to make support of the state’s K-12 education system a high priority; that a “lack of funding” rates the highest on a list of vital issues; and that 61 percent believe teacher salaries are too low.

PPIC’s findings, which were released Wednesday, seem to buoy campaigns by the California Teachers Association and other education groups to sharply increase school spending.

However, it’s not at all certain that, despite their apparent support for spending more, Californians are willing to tax themselves more.

The poll found only tepid support for a pending ballot measure that would create a “split roll” for property taxes, thus increasing levies on commercial property such as office buildings and warehouses.

Moreover, when PPIC asked voters whether they’d vote for “parcel taxes” for their local schools, fewer than half said they would – a far cry from the two-thirds vote margins such taxes must obtain.

The PPIC polling again underscores the essential dilemma for those who want California to sharply expand school spending and raise California’s per-pupil support from middling, vis-à-vis other states, to match the highest-spending states such as New York and New Jersey.

With six million kids in California’s public schools, raising per-pupil spending by $1,000 would cost $6 billion a year – just about what the split-roll proposal would generate for education. Moving into the upper tier of states would require about $5,000 more per pupil or $30 billion a year.

Twice in this decade, voters have approved higher income taxes on the wealthiest Californians on the promise that they would help the schools – and, in fact, per-pupil spending has increased by at least 50 percent in this decade.

Even so, many school districts, including those where teacher strikes occurred, are teetering on the edge of insolvency, largely because their costs for pensions and retiree health care have soared.

By happenstance, as PPIC was releasing its new survey, Pivot Learning, an educational consulting firm, published a new study that details how retirement costs are eroding spending for teacher salaries and for closing the “achievement gap” that afflicts poor students.

“While districts paid approximately $500 per pupil in 2013-14 for employee pension costs, they will pay $1,600 per pupil in 2020-21,” the “Big Squeeze” report said. “As a result, California’s districts will pay $9 billion per year towards employee pensions in the school year 2020-21.”

It’s easy and popular for voters to tell pollsters, or for politicians to parrot, that schools need more money. However, raising it would be a daunting task.

California now has, by far, the nation’s highest income tax rates and has probably reached the practical limit, especially since high-income taxpayers can no longer deduct more than token amounts of state and local tax payments on federal tax returns.

If, as the PPIC poll results imply, Californians want to sharply increase spending on schools, especially for teacher salaries, they would have to tax themselves. To put it in perspective, a $30 billion a year increase in school spending would be the equivalent of a one-third increase in state income taxes or more than doubling state sales taxes.

It would have been interesting for PPIC to ask voters explicitly about tax increases of those magnitudes.