SACRAMENTO, Calif. (AP) -- Charles Munger Sr. is best known as Warren Buffett's right-hand man, an investor who has turned his skill at picking winning companies into a billion-dollar fortune.
He has passed some of his passion on to his children, two of whom are using their considerable fortune to transform California's political landscape this year.
While Molly Munger and her half brother, Charles Jr., are on opposite ends of the political spectrum, both have thrown up significant roadblocks to Gov. Jerry Brown's ballot initiative seeking to balance the state budget through raising taxes.
Republican Charles Munger Jr., a Stanford physicist, has given $35 million to defeat Brown's initiative, which would raise the state sales tax and increase income taxes on the wealthy, and to support a ballot measure that would undercut public employee unions.
His sister has also attacked Brown's initiative, pushing her own ballot measure that would increase income tax rates for nearly all taxpayers and send the money directly to school districts, bypassing the Legislature. She has spent more than $33 million.
A poll released this week shows her Proposition 38 and Brown's Proposition 30 without majority support.
Both Mungers are relative newcomers to California's political scene. They have generally shied away from the spotlight, even as Brown's supporters labeled them the "billionaire bullies" seeking to destroy California's public schools. If voters reject his initiative, Brown has said the state will enact $6 billion in automatic cuts, mostly to K-12.
The siblings are almost universally described by those who have worked with them as driven and intensely focused -- millionaires who ask a lot of questions before they commit to a cause.
California Common Cause, a good-government group, partnered with Charles Munger Jr. on its successful effort to create an independent citizens redistricting commission that would draw state legislative and congressional districts based on the once-a-decade census.
The group's president, Kathay Feng, called it an "excruciatingly long" process answering the detailed, methodical questions he had before agreeing to commit.
He was so thorough he eventually became an expert on the myriad intricacies of redistricting law, she said.
"I think that his approach probably mirrors the way he operates as a nuclear physicist," she said. "He takes something and dissects it and approaches it from 10 different directions before he makes a conclusion about what the best route forward is."
Munger Jr. is a research associate with the SLAC National Accelerator Laboratory at Stanford University, a research lab devoted to experimental and theoretical research in advanced physics.
While he has drawn scrutiny for his multimillion-dollar contributions to two of the highest profile initiatives on the ballot, he also is the primary contributor to Proposition 40, which would keep in place the new state Senate districts that Republicans opposed.
Like her brother, Molly Munger has shown an affinity for researching complex issues. In a PowerPoint presentation to the California State PTA last year, she demonstrated a detailed knowledge of the state's complicated education finance system.
"I think she is very data-driven and analytical," said Don Shalvey, deputy director of the Bill and Melinda Gates Foundation's U.S. Programs Education initiative who has worked with her on education issues. He said she appears to be a deeply curious person.
"I think she would be, you know, equally comfortable in a strong conversation with a bunch of policy wonks and then going out at night to a Grateful Dead concert," said Shalvey, who said he has known her for about seven years.
Both Mungers and their father declined to be interviewed for this story, but the siblings have previously spoken with The Associated Press about their political activism.
Molly Munger explained in March that she was motivated to pursue her ballot initiative this year out of "pain and shame" over the decline of California's public schools and a desire to help repair them.
She traced her own taste for activism to a pivotal point in adolescence, when she persuaded her father to let her leave her private, all-girls school for the more diverse John Muir High School in Pasadena, where the family lived.
She took an interest in the civil rights movement and went on to graduate from Harvard Law School.
After several years as a corporate attorney, she became western regional counsel for the NAACP and later co-founded a liberal-leaning civil rights group called The Advancement Project, which advocates for equal opportunities for disadvantaged children.
While she was a registered Democrat for most of her life, she has been an independent for about a decade.
Both siblings said political debate was frequent in their home growing up. Their father loved to provoke discussions among his blended family of eight children, forcing them to listen to other points of view.
"We're respectful, we get along and we don't consider it a mortal insult if any one of us disagrees. We just expect a reciprocal courtesy," Charles Munger Jr. said during a separate interview in March.
People are not so polite in the political arena, though. The siblings have had to fend off attacks from people who would normally be their allies.
Brown's campaign and other Democrats have criticized them for trying to defeat his tax initiative, saying "the Munger name may soon be synonymous with devastating cuts to California's schools and universities."
Charles Munger Jr. is used to the criticism from Democrats and even his fellow Republicans, many of whom disagreed with his support of the independent redistricting process because it threatened the status quo.
While he was attacked as elitist during the redistricting campaign, it didn't faze his sister from wanting to wade into the political fray.
"She watched that happen and she decided that whatever she wanted to do for the state of California was worth that," Munger said in March of his sister. "You have to find that personally admirable."