He is a Democrat and former governor backed by the public employee unions that won the right to organize on his watch. He rails against Wall Street greed and preaches the virtues of alternative energy.

She is a former corporate executive and billionaire Republican who forged ties with investment bankers and seldom voted until she decided to run for the state’s highest office, vowing to slash spending by shedding tens of thousands of workers from government.

On the core issue facing California — finances — the two agree in principle that the state must rein in spending. But that is where the similarities are likely to end.

As they prepare to do battle over who will become the next governor, Atty. Gen. Jerry Brown and former EBay Chief Executive Meg Whitman bring with them contrasting backgrounds and starkly different approaches to the state’s most pressing problems.

Whitman, who dispatched Republican rival Steve Poizner in Tuesday’s primary, would undoubtedly be a strong ally in the Capitol for influential business leaders, who are pushing her candidacy. Brown, in his current post and throughout his past, has advanced a populist message.

In the state’s moderate middle, where the election will be won, the result may depend on who is perceived as most able to restore the lifestyle and promise that made California great: whether Brown is seen as a progressive visionary or a status quo politician kowtowing to tax-consuming liberal interests, and whether Whitman is seen as a no-nonsense manager who can impose discipline on a government out of control or a lackey of business at the expense of the average citizen.

Whitman, 53, proposes scaling back state pensions, making employees work longer before they can collect retirement pay and cutting 40,000 state jobs. She says she would also cut costs by improving computer technology, capping state spending and curbing debt.

She told farmers last month in Modesto: “Caltrans built a $3.4-million rest stop on one of our highways. I want to live in that rest stop — $3.4 million?… We have a government we can no longer afford.”

Her fiscal agenda is familiar. Like Gov. Arnold Schwarzenegger, she proposes to save money by finding fraud in social programs serving the old, disabled, unemployed and poor; paring redundant agencies; and reducing lifetime limits for welfare. But in such efforts she would face a hostile, Democrat-controlled Legislature that is not required to take orders from a chief executive.

Brown, 72, was known as a tight-fisted governor from 1975 to 1983. He believed in “limits,” which translated to a lack of investment in the roads, universities and other infrastructure that his father, Pat Brown, had built as governor before him.

He has been vague about how he would tame the budget, but as governor and in this race, his biggest allies have been the public employee unions whose agendas include preserving big, expensive healthcare and social service programs. Yet he says he would slow the growth of social programs.

“I think we’re going to have to look at every one of them,” Brown said in March. “I don’t see a draconian cutback on Day One, but I see over the next several years an aligning of what we spend with what we collect.”

Brown says he would not support a tax increase unless voters approved one; Whitman says she would give tax cuts to businesses that would create jobs and bring in more revenue. Her aides declined requests for an interview with her.

Noting that “I travel Southwest, she has a private jet” (Whitman’s aides say her plane has a propeller), Brown questioned the fiscal conservatism of a candidate who spent more than $80 million, most of it her own, to win the primary: “She handles money one way. I handle it another way — far more frugally.”

But as governor, Brown signed laws allowing unionization of government employees, whose organizations have grown into California’s most powerful Democratic interest groups.

“You have somebody that’s been part of a system — both he and his father in this state, over the last 50 years — and represents a line of more power to the unions, bigger pensions, bigger state spending,” said Duf Sundheim, a former state Republican chairman.

On social issues, both are closer to the political center than to the extreme elements of their respective parties.

Brown has traditionally been socially liberal. He opposes the death penalty. He worked in India with Mother Teresa.

An early proponent of solar and other alternative energy and a champion of the environment, he has worked aggressively as attorney general to implement California’s law to reduce global warming. He sued the Bush administration for Schwarzenegger when it blocked California’s tailpipe emissions standards.

But on other issues, such as law enforcement, Brown is further to the right. He has opposed federal judges’ push to release inmates from the state’s overcrowded prisons and calls, as Whitman does, for reining in healthcare spending on prisoners. Like many Republicans, Brown says local government should have more power.

In the past, Whitman has appeared socially moderate to liberal on abortion and the environment, donating $300,000 to the Environmental Defense Fund to protect the Delta habitat and taking an Arctic cruise to study global warming. But this year she has framed her positions more conservatively, with an emphasis on helping business.

She has said recently that it is more important to get water flowing to farmers than to take steps to protect endangered fish. And she has proposed delaying the state’s global warming law, contending that it would hurt the economy.

Whitman has also suggested putting a moratorium on other government regulations. In her policy agenda, laid out to voters in a glossy 46-page booklet, she says every state agency should identify “any negative impact” of new rules. Brown, on the other hand, has worked to enforce many state regulations, dragging California companies into court on consumer and worker protection issues. And he has blamed Wall Street for the mortgage meltdown and economic crisis that have impoverished many Californians.

And the two differ on one of the mostly highly charged issues of the primary campaign, which Brown largely sat out for lack of a major opponent. Whitman has promised to make it much harder for illegal immigrants to be in California. She opposes amnesty for those here illegally and says she wants tougher enforcement at the border. And she says she’ll go after employers who hire undocumented workers.

Brown has avoided using his powers as attorney general to pressure the federal government to enforce immigration laws. In March, he accused Whitman and Poizner of pandering on the issue.

“Yes, protect our border. Yes, enforce the law,” Brown said. "[But] I’m not going to scapegoat immigrants and public servants and poor people.”

michael.rothfeld@latimes.com