Arnold Schwarzenegger and Maria Shriver at a January funeral Mass for her father, Sargent Shriver, in Potomac, Md. (J. Scott Applewhite/ AP)

How did it stay a secret so long?

For at least 10 years, throughout a spectacular and closely-scrutinized political career, Arnold Schwarzenegger managed to hide the existance of a love child with a member of his own household staff.

Only now, after leaving the governor’s office and splitting from his equally famous wife of 25 years, are we finding out. (** Read earlier: Schwarzenegger acknowledged child with household staffer before split with Maria **)

“It’s almost mindboggling that information like this did not become public over his political career,” said veteran California GOP strategist Dan Schnur, who now teaches at the University of Southern California. “If this had come out when he was running for governor, he wouldn’t have gotten elected.”

Yet somehow Schwarzenegger, his lover and whoever else knew about the baby managed to keep the secret for at least a decade. Political consultant James Carville called it “stunning” that this never bubbled up. “I would not be surprised if a lot of money changed hands,” he told us. (Update, 5/18: Schwarzenegger, the housekeeper, Shriver: Your questions answered)

Which is the critical point for Steve Mindel, an expert on California family law.

Mindel said he suspects that a DNA test was performed to establish paternity (the staffer was married to another man when the child was born), and then Schwarzenegger made child-support arrangements.

“I can’t even fathom that he has a checkbook and writes checks for, say, the gardener,” Mindel said. Average child support from a “high net-worth individual” like the former movie star would be $15,000 to $30,000 a month, which means it’s highly likely that a business manager or accountant would be aware of the child, even if his wife Maria Shriver was not.

But those expenses don’t show up in public filings; politicians are only required to disclose money coming in, not money they spend. “The personal disclosure statement details the official’s economic interests — where they’ve received money or where they have money invested,” said Roman Porter, executive director of Fair Political Practices Commission. Unless Schwarzenegger was using campaign donations (the offense for which John Edwards is being investigated), the child support would remain a private matter.

Editors and reporters at the Los Angeles Times, which broke the story, declined to answer questions about their big scoop, leaving several aspects of the story a mystery: what year the child was born, or what job the mother held in the household, or why the story was published now. Such details were kept out of the story to protect the identities of the mother and child, according to people at the Times, reports our colleague Paul Farhi.

The paper was criticized by some Schwarzenegger supporters for a story before the 2003 election: More than a dozen women said they had been groped by Schwarzenegger when he was a movie star. (He at first denied the allegations, but later apologized.) Around the same time, a British tabloid implied that the Times was pursuing a story about a Schwarzenegger love child — which led some to conclude that the paper has been sitting on this story for eight years. “Unequivocally not true,” Times spokeswoman Nancy Sullivan said Tuesday.

Shriver released a statement Tuesday calling this “a painful and heartbreaking time” and she appealed for “compassion, respect and privacy as my children and I try to rebuild our lives and heal.” The couple’s 17-year-old son, Patrick, tweeted: “Some days you feel like [expletive]. . . yet i love my family till death do us apart.”

A version of this story will appear in Wednesday’s Washington Post

Read earlier: Schwarzenegger acknowledged child with household staffer before split with Maria

Arnold Schwarzenegger and Maria Shriver, a political couple “in transition” after 25 high-profile years (photos), 5/10/11

A brief history of the political “love child”, 1/11/10

Photo gallery: Politicians who had children out of wedlock