What happened
Oprah Winfrey plans to campaign for Democratic presidential hopeful Barack Obama in Iowa and other key, early-voting states, Obama’s campaign said Monday. Obama’s Iowa press secretary Tom Vietor said Winfrey’s support would help Obama “reach out” to fans of her talk show, but Drake University political science professor Dennis Goldforb said endorsements are “nice little trophies” that don’t “mean that much.” (Des Moines Register)

What the commentators said
Celebrity endorsements mean nothing in politics? said Eugene Robinson in The Washington Post (free registration). We’ll see about that. When Winfrey made “Anna Karenina” a monthly selection for her book club, Leo Tolstoy’s dusty classic instantly became a best seller. If she can work the same magic for Obama, the Illinois senator’s rivals could be in trouble.

“Big endorsements are hardly a guarantee of political support,” said Sheldon Alberts at Canada.com. “But Oprah is a different sort of celebrity altogether.” She can “sway votes among Democratic women, who are vital to Hillary Clinton’s campaign,” and “if nothing else, the Oprah-Obama show is worth millions in free media coverage.”

“Mark me down as more than a bit skeptical,” said Mark Halperin in Time.com. Appearing at a few December rallies with Oprah at his side will give Obama “campaign cash, celebrity, excitement and big crowds,” but it won’t help him with the one thing “he has needed all along—for voters to see him as ready to be commander in chief by January 2009.”

Enlisting the support of an "uber-listener" like Oprah gives Obama some nice "rental empathy," said Dahlia Lithwick on Slate's XX Factor blog. Now he can tell moms, "Look, I don't know what it's like to stay at home with two kids, and a basket of ironing, but Oprah sure does." But don't forget that Hillary has Bill Clinton on her side, so this is shaping up to be "an Olympics of hearing your pain."