SAN DIEGO – In 2012, California voters approved Proposition 30, which greatly increased personal income taxes for those making more than $250,000 per year, as well as the state’s sales tax.

Billions of dollars of the resulting revenue were directed to the state’s public schools, intending to halt teacher layoffs, end cuts to student programs, and balance school budgets.

But public schools are an arm of government, and if there’s one constant truth about government, it’s this – the more money it receives, the more it spends.

A 2016 report published by the Voice of San Diego provides evidence of that ugly fact.

The news service took a close look at spending at San Diego County’s five largest school districts, four years after the adoption of Proposition 30.

“From San Diego Unified to Poway Unified to Chula Vista Elementary, officials upped their spending dramatically in recent years, budget documents show,” the news report said. “Some — like San Diego Unified — must now slow their roll to pay the bills next year.

“Every district — except one — is planning to drain the reserve fund to near-minimum levels to accommodate increased spending in the next two years, budget records show.”

The ugliest budget numbers came from the San Diego Unified school district, where the school board approved an across-the-board four percent raise for all employees in November 2016, then a month later started planning to make massive budget cuts to eliminate a projected $117 million deficit.

In the Sweetwater Union High School District, revenues increased by more than $113 million between 2012 and 2016, but spending increased by more than $127 million.

In the Poway Unified School District, revenues increased $113 million between 2011 and 2016, but spending increased by $130 million, according to the news report.

“Poway’s reserve fund is projected to end the year at $35 million, or 9.25 percent,” the report said.”The district plans to continue spending the fund down in the next two years, leaving just $8.25 million in 2018-19, or 2.23 percent.”

In the Chula Vista Elementary district, annual revenue increased by about $57 million between 2013 and 2016, but expenses increased by more than $73.5 million, according to the report.

The school district certainly didn’t help itself by granting all employees a six percent raise in 2016.

“The district — which serves 30,000 students — plans to outspend its revenues this year and the next two years and will turn to the reserve fund to help fill the gap,” the news report said.

In the Vista Unified School District, the 2016-17 plan was to spend $20 million more from the general fund than it took in. Officials planned to dip into savings to make up the difference.

“The district plans to reduce its reserve fund from $12.2 million this year, or 5 percent, to $7.77 million by the end of 2018-19, or 3 percent,” the news report said.

We’re pretty sure the California voters who supported the big tax increase – including those in San Diego County – did so hoping that schools would balance their budgets and provide for student needs.

They have a right to be disappointed and angry.