Her husband, Gov. Arnold Schwarzenegger, gave his endorsement to John McCain on Thursday.
Shriver’s appearance drew thunderous applause in the auditorium, which was about 2/3 full and was an audience mainly of women. But it came as a surprise, with the campaign having been informed only earlier today.
"I believe that elections are a lot like life," Shriver said. "They are made up of moments."
She said she made up her mind only on Sunday morning, and referred to a quote from Eleanor Roosevelt that she said she has posted above her computer: "Do one thing every day that scares you."
"This is my thing for today."
Shriver’s appearance came at the end of an hour-long rally that included Caroline Kennedy, Oprah Winfrey, Stevie Wonder and Michelle Obama.
One of her reasons for backing Obama, Shriver said, is "I’ve seen how hard it is to bring people together. If that’s not your whole mantra, ain’t going to happen."
“There is no place I wanted to be but here today,” said Shriver. “This election is about a moment. This is a moment not just for the United States of America, not just for the Democratic Party, but this is a moment for California. The more I thought about it, I thought, if Barack Obama was a state, he’d be California. Think about it: diverse, open, smart, independent, bucks tradition, innovative, inspiring, dreamer, leader.”
“But this is a moment. It’s a moment to have a conversation with yourself. Do I believe in an America that’s about unity, about coming together, it’s about seeing beyond the labels? We’ve got to see beyond the labels that divide us. And if that’s the kind of America I want, I think it will be very clear to you what you should do on Tuesday.”
Shriver’s backing could help Obama draw more women voters — one of Hillary Clinton’s strengths. The UCLA event, held just before the start of the Super Bowl, was aimed at a female audience and evoked a theme: Just because a candidate is a woman doesn’t mean that women should automatically support her.
Winfrey noted the criticism that she has received for backing Obama, including being called a "traitor to women." Critics have posted comments on her website also upset, charging that she is backing Obama because he is black. Winfrey called the comments "insulting."
"Every part of me believes in the empowerment of women," Winfrey said. "But the truth is, I am a free woman. A free woman. And being free means who can think for yourself."
She added, "I’m voting for Barack Obama not because he’s black. I’m voting for Barack Obama because he’s brilliant."
Winfrey made her return to the campaign trail after stumping with Obama in New Hampshire, Iowa and South Carolina.
Here’s Oprah’s appearance:
Here’s Maria Shriver’s appearance.