United States:More women voters still need to be won over from Clinton's camp, writes Denis Stauntonin LA.
The event was only announced the day before and most Americans were watching the Super Bowl game, but thousands made their way to a vast arena at UCLA on a rare rainy Sunday afternoon in Los Angeles to see Oprah Winfrey, the first lady of television, introduce the woman she wants to see as America's next first lady, Michelle Obama.
"I believe the change has already come, California," Winfrey declared as she looked out over the crowd of faces, almost all of them young, most of them women, and many of them black.
With polls showing Barack Obama closing in on Hillary Clinton in California, the Obama campaign sees a chance to pull off a dramatic upset today by winning the biggest state in play on Super Tuesday. To succeed, however, Obama must expand his appeal to the women voters who have been Clinton's most loyal supporters, persuading them that they shouldn't make their choice on the basis of gender.
"I have been a woman my whole life and every part of me believes in the empowerment of women," Winfrey said as she told the audience about angry messages she had received since she endorsed Obama.
"But I'm a free woman and being free means you get to think for yourself and to decide for yourself what you should do."
Winfrey is the biggest star in a growing constellation of celebrities who are supporting Obama and she was joined onstage at UCLA by Stevie Wonder, whose Signed, Sealed, Delivered, I'm Yoursends every Obama rally.
Earlier, Caroline Kennedy spoke about how she had found at last a candidate who could inspire her the way her father, John F Kennedy, inspired millions of Americans. But it was Michelle Obama who gave the most substantial political speech, arguing that her husband's candidacy represented a unique historic opportunity for the country.
"I am married to the only person in this race who can heal this nation," she said.
She avoided any direct mention of Clinton, but rebutted each charge levelled against her husband, one by one, including Clinton's claim that she is better prepared to stand up to Republican attacks.
"We live in Chicago, people. Don't worry about whether Barack is tough enough for the Republicans," Obama said.
Whereas the candidate approaches the issue of race obliquely, his wife confronts it directly, describing her upbringing in a working-class black household on the southside of Chicago, attending local public schools. "When you look at me, I don't want you to see the next first lady," she said.
"I want you to see what an investment in public education looks like."
She spoke about a 10-year-old black girl she met in South Carolina who told her what an Obama presidency would mean for her. "It means that I can imagine anything for myself in this world," the girl said.
Obama's success in the campaign so far has owed much to his promise to heal the racial wounds that scar the US, but California could test the limits of his cross-racial appeal as he seeks to win support from Latinos, most of whom support Clinton.
California polls show only one in five Latino voters supporting Obama, a deficit that could cost him dearly in the southern part of the state.
Obama's best hope of counteracting the imbalance in the Latino vote may lie in the 20 per cent of Californians who describe themselves as independents, who are allowed to vote in today's Democratic primary but not in the Republican one.
Obama's appeal to independents received a surprise boost when California's first lady, Maria Shriver, appeared at the UCLA rally, telling the audience that she had only decided to endorse Obama that morning.
Shriver, a member of the Kennedy clan whose husband, Arnold Schwarzenegger, has endorsed Republican John McCain, said Obama was a perfect fit for California.
"If Barack Obama was a state, he'd be California," she said to wild applause.
"Think about it. Diverse. Open. Smart. Independent. Bucks tradition. Innovative. Inspirational. Dreamer. Leader."
Shriver said that an Obama presidency would create a transformative moment, not just for Democrats or even for the US, but for the entire world.
"He's not about himself. He's about the power of us and what we can do if we come together," she said.
"He is about empowering women, African-Americans, Latinos, older people, young people. He's about empowering all of us."
Despite Schwarzenegger's endorsement, McCain faces a mounting challenge in California from former Massachusetts governor Mitt Romney, who flew to Long Beach last night for an 11th-hour rally.
The latest Reuters/Zogby poll gives Romney an eight-point lead in California, although McCain is ahead in most other Super Tuesday states.