The campaign that for months was dominated by talk of schools, the state's $19 billion deficit and jobs has become a swirl of accusations pitting the word of Whitman, the billionaire former eBay chief executive, against a 39-year-old maid who worked in her home for nearly a decade.
Whitman says the woman provided a valid but fraudulently obtained Social Security card and driver's license when she was hired through an employment agency in 2000. At issue is whether Whitman knew about a 2003 letter from the Social Security Administration that raised discrepancies about her housekeeper's documents -- a possible tip-off that she could be in the U.S. illegally.
The letter is at the center of claims by Nicky Diaz Santillan that Whitman and her husband knew for years about her legal status but kept her on the job anyway at their Silicon Valley home.
Seeking to quiet the uproar, Whitman tried to turn the discussion in another direction. "This is a distraction on what I think Californians really care about," she said, referring to unemployment and public schools.
But damage might already be done.
"When news headlines are saying 'Whitman hired an illegal alien,' you have a problem," said Jack Pitney, a political scientist at Claremont-McKenna College in Claremont, Calif. "A Republican in California has a tough sell among Latinos to begin with. This makes it tougher for her."
On Thursday, Whitman disclosed that her husband might have seen the 2003 letter and jotted a note on it telling the housekeeper to "please check this."
For two days, Whitman forcefully denied receiving any such letter and said she fired the $23-an-hour housekeeper last year immediately after learning she was illegal. But Whitman's husband changed course Thursday after a letter surfaced with what appeared to be his handwriting, forcing him to say he may have been aware of the correspondence back in 2003.
Whitman has denounced the allegations as a "baseless smear attack" by Democratic challenger Jerry Brown in what has become a dead-heat race to run the nation's most populous state. Hispanics are projected to comprise just 15 percent of voters in the Nov. 2 general election, but both sides have aggressively targeted them as potential swing votes, with Whitman spending millions to court them.
Now, the focus is on whether the billionaire GOP nominee for governor will take a polygraph test to respond to allegations brought by a celebrity-seeking attorney and her mysterious housekeeper client. Whitman said she would be willing to undergo such a test.
Revelations about the illegal housekeeper have also thrown Whitman's carefully managed campaign completely off track and opened the door for Democrats to accuse her of hypocrisy.
Whitman has called for tougher sanctions against employers who hire illegal workers, and the fact that she employed an illegal immigrant maid from Mexico for nine years could undermine her credibility.
After Whitman's denials, the housekeeper and lawyer Gloria Allred produced a copy of the letter Thursday that they say shows Whitman's husband, Dr. Griffith Harsh IV, partially filled it out.
Allred said the housekeeper recognized the writing as belonging to Whitman's husband, and a handwriting specialist may be brought in to analyze her husband's penmanship. She claims it could prove that Whitman and her husband knew years earlier that Diaz Santillan was not a U.S. citizen.
In a statement released by the campaign, Harsh said he did not recall receiving the letter, although it's possible he scratched out a note asking Diaz Santillan to follow up. He noted, however, that the letter does not say Diaz Santillan is illegal, it merely asks for more information.
"The essential fact remains the same, neither Meg nor I believed there was a problem with Nicky's legal status," the husband said. "The facts of this matter are very clear: Ms. Diaz broke the law and lied to us and to the employment agency."
Campaign adviser Rob Stutzman said "it's reasonable" the letter could be authentic, but added the campaign has questions about its whereabouts for seven years and if it is legitimate. At one point Thursday, the campaign said Diaz Santillan may have intercepted the letter since she was in charge of the mail at the house.
The story has consumed two full days of news cycles just as Whitman and Brown are preparing for a Saturday Spanish-language debate that will include questions of importance to the Hispanic community.
One of the state's largest public employee unions immediately released a Spanish-language attack ad accusing Whitman of a double standard on illegal immigration.
Whitman, who has revealed few details about her personal life since announcing her first run for office last year, was forced to spend 45 minutes answering questions from reporters about what she knew and when she knew it, her husband standing awkwardly by throughout.
"You know, I've only been in politics for two years. I'm just getting used to the smear politics, I'm just getting used to the politics of personal destruction," she told dozens of reporters hastily gathered at a hotel in Santa Monica.
Whitman has spent a record $119 million of her own money on the race, and her campaign has been marked by its uncanny ability to stay on message. That marks a notable contrast with Brown, the state's attorney general and a former governor known for talking off-the-cuff, sometimes too much.
The timing of the allegations so close to the Spanish-speaking debate, the lack of extensive documentation, and Allred's Democratic ties left her open to questions about motive. Allred once gave money to Brown, and she was a Hillary Rodham Clinton delegate at the Democratic National Convention in 2008.
Allred, who is well-known for orchestrating media stunts, has not permitted Diaz Santillan to answer a single question from reporters over two days of news conferences. The former housekeeper read a brief, prepared statement Wednesday that alleged brusque treatment during her nine-year tenure. Whitman said it was "not the Nicky I know."
Allred said Thursday she is not providing any financial support to her client and added her involvement with Diaz Santillan started "within the last week." In a radio interview later Thursday, Allred declined to discuss who is paying her.
Two days after she made the allegations that reordered the race for governor, Diaz Santillan remains a mystery. Virtually nothing is known about her activities or whereabouts from the time Whitman fired her in June 2009 until she appeared Wednesday with Allred at her Los Angeles law office.
In her 2000 employment application, Diaz Santillan revealed she went to high school and college in Mexico City and says she would like to go back to school to take computer administration. The mother of three said she has 11 brothers and sisters, eight of them living in the San Francisco Bay area. Whitman's campaign says Diaz Santillan used her sister's documents in her fraudulent application.
Whitman was repeatedly asked why she didn't just own up to this huge political liability earlier to avoid a late election-cycle surprise such as this, particularly since she has repeatedly stressed the need to hold employers accountable for hiring illegal workers.
She said she didn't want to subject Diaz Santillan to the scrutiny -- and left unsaid, deportation -- that could have resulted from her reporting it. Whitman also noted that in California, employers bear no responsibility to report illegal workers, only to not knowingly hire and employ them.
"Because Nicky had worked for us for 10 years, I was very fond of Nicky and I didn't want to make an example of her. It's not an obligation of the employer to turn in illegal employees," she said.