Exclusive: Oprah Says Vote for Obama Isn't Vote Against Clinton

Dec. 12, 2007 — -- As soon as Oprah Winfrey endorsed Sen. Barack Obama, D-Ill., for president, the buzz began about her potential to sway an election.

In an exclusive interview with ABC News' Diane Sawyer, the media mogul seemed to downplay the power behind her seal of approval, saying that just because she is supporting Obama doesn't mean she is against any other candidate.

"I've always said this, that my being in support of Barack Obama is not my being against Hillary Clinton or anybody else," Winfrey said. "It's just that for this moment in time, this is what I know I am supposed to be doing. I feel compelled to do this. So my vote for is not a vote against anybody. It's just a vote for."

Winfrey said she hasn't talked to Clinton since her Obama endorsement, but she left open the possibility of changing her mind down the road.

"Well obviously, Obama's great because I'm believing that the person that I'm speaking up for is gonna take it all the way," Winfrey said. "And then if that doesn't happen, I might readjust my thinking."

Whether her endorsement will have any tangible effect on the race remains to be seen, but Winfrey drew enormous crowds during campaign appearances with Obama in South Carolina this weekend.

And she is taking her role as a political spokeswoman seriously. She told Sawyer that she wrote her own speech before events instead of giving an impromptu talk, as she often does.

"I had written a speech because I didn't trust myself just to stand up there and talk, and this was too important of an issue, I thought, for me to be up there rambling around," she said.

"So the night before I was [up] at 3 a.m. still working on my speech. Yes, I was. And then I heard somebody say that his [Obama's] staff helped me write the speech, which insulted me, since I was like doing my homework late at night, working on it myself. I didn't appreciate that," Winfrey said with a laugh.