DES MOINES, Iowa — Television star Oprah Winfrey, an influential voice in American popular culture and one of the most successful blacks in the world, urged Iowans on Saturday to use their first-voting status to give Barack Obama the momentum to overtake Hillary Clinton for the Democratic presidential nomination.
"I'm here to tell you, Iowa, he is the one," the billionaire, philanthropist and top-rated talk-show host told a crowd estimated at more than 15,000 who navigated snow-crusted roads to see her stump for the Illinois senator at Hy-Vee Hall in Iowa's capital city.
Without naming Clinton, Winfrey argued that Obama's community activist background is more valuable than the former first lady's more extensive Washington experience and that he could better unite the nation. Obama, she said, has a "new vision" for the country.
Since the 1980s, Winfrey's endorsements have sold millions of books, created the likes of Dr. Phil, integrated black culture into swaths of white America and brought instant credibility to various causes and charities. Her appearances for Obama, the first presidential candidate she's campaigned for, will test whether the "Oprah effect" extends to American politics.
"I understand the difference between the book club . . . and this critical moment in our nation's history," she said. "I am not here to tell you what to think. I am here to ask you to think seriously — about a man who knows who we are and who we can be."
Obama looked star-struck as he told the crowd how much he loved and appreciated her.
"You want Oprah as vice president?" he asked, and the crowd cheered. "That would be a demotion, you understand that." He then delivered a standard stump speech, talking about his desire to end the Iraq war, expand health care and college affordability and shared his biography.
He also sought to frame his candidacy in the context of Winfrey's ability to succeed against the odds for most blacks. "My presence here today is unlikely just like Oprah is unlikely," he said. "We share that in common."
The mixed-race, heavily female audience began arriving two hours before the mid-afternoon event. The mood was raucous and festive, the lines to get into the standing-room-only hall grew longer and the crowd fed off its own energy.
The attendees were a mixed bag. Some were committed Obama supporters. Others were primarily Winfrey fans.
"I love Oprah, she's like my role model," said Adrienne Williams, 31, who said she's trying to decide between Clinton and Obama. She said that Winfrey's opinion could influence her vote.
But Kay Bolton, 68, who slipped out a few minutes into Obama's remarks, admitted that she's already a committed Clinton voter and said that hadn't changed. "We respect Obama, but we're here to see Oprah," she said. "She should run for president herself."
Then there was Liz Ward, a middle-aged businesswoman who said, "I'm a Republican and I'm not even a huge Oprah fan. It's just the place to be." Ward said she probably wouldn't have come to an Obama appearance otherwise, but that she was "open" to voting for him. "None of the Republican candidates do anything for me."
Des Moines was the first of Winfrey's four planned stops with Obama on a two-day blitz that was to continue to Cedar Rapids, Iowa, and then to the early voting states of South Carolina and New Hampshire.
In South Carolina, where black voters comprise half the Democratic electorate, the Obama campaign changed the venue for Sunday's planned appearance in Columbia from an 18,000-seat arena to an 80,000-seat stadium to accommodate the anticipated crowds.
Experts, however, say that most celebrity endorsements have little impact, especially in caucus states such as Iowa, where only the most dedicated voters participate.
But if former president Bill Clinton is his wife's most powerful endorsement, Winfrey may be Obama's best answer.
David Redlawsk, a University of Iowa political scientist, said that Winfrey already has generated free publicity for Obama and could bring into the loop Winfrey fans who haven't focused on the election.
But Redlawsk was dubious of her impact on Jan. 3. "It's not clear that any of that matters when it comes down to getting people out on a cold winter's night to caucus," he said.
He predicted a greater effect in South Carolina because it holds a primary election rather than a caucus and because Winfrey may be poised to convince more black voters Obama is electable.
Obama, 46, a first-term Illinois senator and the first black candidate to compete this strongly for president, has been holding second place in national polls behind Clinton, but in recent polls the gap between them has narrowed.
Obama, however, is still struggling to convince many fellow blacks that he could win a general election and to woo older Democratic women who gravitate to Clinton.
Winfrey, 53, has had the nation's No. 1 talk show for 21 consecutive seasons. It reaches 46 million unique viewers each week, according to CBS Television Distribution. Many share traits of Clinton fans: three-fourths are women, more than half are over 50, and viewers' median income is $46,000.
Winfrey's talk show is the No. 2 syndicated program among adult women in Iowa, behind "Wheel of Fortune", and the No. 1 syndicated show among women in South Carolina and New Hampshire.