If the definition of insanity is “doing the same thing over and over again but expecting different results,” Democratic legislators upset with Gov. Jerry Brown’s relatively parsimonious revised state budget seem bound to test that rule.

No sooner had Brown released his May budget revise Tuesday morning than Democrats were complaining that the governor’s plan just didn’t have enough spending.

They didn’t use those exact words, of course, since these are politicians. They each praised the governor for balancing the budget and agreed this is no time for unnecessary spending.

It just happens, however, that each legislator has pet projects that are not only necessary but also key to the future of California and its people.

For state Senate President Pro Tem Darrell Steinberg, it’s mental health programs and dental care for the poor. For Assembly Speaker John Perez, it’s college scholarships for middle-income students and increased court funding. State Sen. Mark Leno wants to “invest in other areas that are critical to our economic growth and social welfare” while state Sen. Leland Yee says, “It is time to undo the damage done to California’s most vulnerable citizens.”

You get the picture.

But here are two words for those Democrats upset with Brown’s budget: Gray Davis.

Heck, let’s make it four words: Arnold Schwarzenegger.

When Davis took office back in 1999, California was in the middle of the dot-com boom, which sent state revenue soaring. The governor and the Democrat-led Legislature, convinced the party would never end, started expensive new programs, boosted pay and pensions and signed off on budget hikes of 15 percent or so.

When the boom went bust, state finances were quickly awash in deficits and red ink and Davis got recalled.

Now Perez and other Democrats are complaining that Brown’s budget and its revenue forecasts are just too pessimistic and suggesting they will be using other, more spending-friendly numbers expected from the Legislative Analyst’s Office when it comes time to negotiate with the governor.

While the Davis years might as well be in the far, fuzzy past when dinosaurs walked the earth in these days of term limits, there are still plenty of legislators who were there when Schwarzenegger was proclaiming himself an eternal optimist.

It showed in his budgets, which too-often depended on a federal money fairy to arrive in Sacramento and sprinkle cash on a deserving California.

You may remember how that worked out.

Pessimism is a good thing when it’s time to draw up a budget. It’s unfailing optimism that gets legislators – and the state – in trouble.

It wouldn’t be a surprise if Brown and his finance team were cherry-picking the budget numbers and trying to cast the gloomiest light possible on California’s future finances. After all, the governor has been in and around state politics for his entire life and knows the unrelenting pressure to spend every available dollar on the unquestioned needs of the state.

“There’s a reason why this budget was always in deficit: Because there’s a lot of needs out there and there’s very articulate advocates,” Brown said at a news conference Tuesday. “And I’m trying to find the right balance between spending and holding the line.”

With the economy healing but not healthy, there’s every chance that the unexpected boost in revenues was a one-off that won’t be repeated next year. And Davis showed the disaster that comes when long-term obligations have to be paid with short-term – and fast disappearing — money.

That’s why one of Brown’s biggest new expenditure in the revised budget is $1 billion to help school districts prepare for implementing the new “common core” standards by buying new books, training teachers and providing the technology needed to improve and refocus education in the state.

It’s a one-time grant made with possibly one-time money.

But programs, even restored ones, have a life span that all too often outlives – and outgrows — the money to pay for them. And Brown has argued that it doesn’t make sense to bring back something like dental care for Medi-Cal clients if you just have to pull it away if the economy turns sour in a year or two.

“This is not the time to break out the champagne,” the governor said. “Anybody who thinks there’s spare change around hasn’t read the budget.”

Democrats are likely to test Brown’s resolve on issue after issue between now and the June 15 budget deadline and it will be interesting to see just how much of his plan the governor can hang onto.

One plus about a pessimistic outlook, though, is that any surprises are happy ones. And Californians are way overdue for a run of good news.

John Wildermuth is a longtime writer on California politics.