Gov. Arnold Schwarzenegger has pointedly refused to endorse fellow Republican Meg Whitman in the race to succeed him and has stayed largely quiet on most of the major ballot measures.

But he is campaigning across the state with remarkable passion to defeat Proposition 23, a measure that would suspend California’s landmark global warming bill, one of the signature achievements of his administration.

“You have to be aware that whatever you do can be undone by outside forces,” Schwarzenegger said in an interview with the Mercury News, referring to the Texas oil companies that are the primary financial backers of Proposition 23. “It’s a great battle between good and evil — it’s like a movie. You have the villain dressed in dark black, and the good guys in white and green.”

Proposition 23 would suspend California’s climate change law, known as AB 32, until the state’s unemployment rate, currently at 12.4 percent, drops to 5.5 percent or less for four consecutive quarters, something economists say is unlikely to happen anytime soon. Advocates with the Yes on 23 campaign argue that AB 32’s strict regulations on greenhouse gas emissions place too high a burden on the state’s struggling manufacturing base and question Schwarzenegger’s efforts.

“Voters are probably wondering why the governor is not spending as much time on finding a real solution to California’s $19 billion budget deficit and record-high unemployment as he is on opposing a measure that would save California families billions of dollars in increased energy costs and protect more than a million jobs that would otherwise be lost as a result of moving ahead with the state’s global warming law,” said Anita Mangels, communications director for the Yes on 23 campaign.

But the governor believes it is possible to protect the environment and expand the economy at the same time, and his knowledge of climate change science and public policy has deepened in the four years since he signed AB 32.

And it’s not just talk: He and Maria Shriver, his wife, agreed to hold a No on 23 fundraiser at their home in the Brentwood neighborhood of Los Angeles.

“When the economy is bad, environmental issues are vulnerable, and they see a great opportunity to move in and go for the kill,” Schwarzenegger said. “We have to be very strong and push back. I will push back. They are raising money and we are raising money.”

“This is not a political play for him,” said Adam Mendelsohn, a longtime political adviser. “He genuinely feels like this is important, and he will often complain that people take shortsighted views. He thinks about California for the next generation.”

Former state Assembly Speaker Fabian Núñez credits Schwarzenegger, a pro-business Republican, for making climate change a mainstream issue.

“Arnold is throwing everything into this fight,” said Núñez, a Democrat who negotiated many of the details of AB 32. “He’s putting the Arnold brand into this. He’s been pushing really hard on the oil companies, and he’s doing a great job.”

A Sept. 26 Field Poll found that most voter blocs agree with the governor and oppose Proposition 23. The major exception is Republicans, who support the initiative by a 47 percent to 33 percent margin. That makes Schwarzenegger’s involvement all the more important, particularly since conservative tea party activists throughout California have coalesced around Proposition 23.

Other associates say his interest in climate change has grown because he regularly travels the world — he attended the December climate talks in Copenhagen — and sees firsthand how global the race for cleantech leadership is. The governor has always been fiercely competitive.

Schwarzenegger recently returned from China, which is fast emerging as the world’s cleantech powerhouse and is moving forward with a set of nationwide energy policies that are spurring cleantech manufacturing and domestic demand for wind, solar power and electric vehicles.

One example: China has set a “Renewable Portfolio Standard” that calls for at least 15 percent of the country’s energy to be procured from non-fossil fuels by 2020. Sen. Jeff Bingaman, D-N.M., has introduced a similar bill in Congress but has not gotten the 60 votes needed to pass it, a struggle likely to get much harder after the November elections if Republicans gain seats in the Senate.

Washington’s inaction on climate change and energy policy angers the governor. The Austrian immigrant is mystified that his adopted home country — the nation that created the personal computer industry and put a man on the moon — seems content to hang back on such a critical issue.

“I am furious about the fact that America is not a leader,” he said. “China is beating us in a lot of different areas, like high-speed rail. They will be the biggest manufacturer of solar. They are much more aggressive than the United States. And we are being watched. When I was in China I was asked about Prop. 23. The thing that really bothers me is that we’ve been talking about energy since the 1970s, but we’ve never led — we’re letting other countries do it first.”

Contact Dana Hull at 408-920-2706. Follow her at Twitter.com/danahull.