It's on -- the great war of the celebrity surrogates has been joined, as American icon Oprah Winfrey announces she'll campaign with Barack Obama in the early states next week.

Winfrey, from Chicago, of course, endorsed Obama very early on, although she has hosted on her show and been very gracious to Hillary Clinton and the Edwardses.

Winfrey has generally abstained from using her enormous influence and audience to influence American politics, but her friendship with Barack and Michelle Obama extends deep enough, and, perhaps, the teachable moment is just too tempting enough for her to bear.

The Clinton campaign has been worried about the prospect of Winfrey campaigning. She is not only, of course, the richest African American woman in the world, she is probably the most popular woman in the United States, and, like Obama, her appeal -- here's that offensive T-word -- transcends -- every barrier that is put up in her way. The Clinton campaign needs women -- married women, single women, upscale and downscale-- to not have second thoughts about Hillary, especially in the early states. Winfrey's highest audience, incidentally, is among working class women, precisely the sub-demographic group that Clinton absolutely needs to win.

Obama and "Ms. Oprah Winfrey" will campaign in Des Moines and Cedar Rapids on Dec. 8, and then Columbia, South Carolina on Dec. 9 and Manchester, NH later that day. Judging by the online real estate devoted to her appearances, the Obama campaign wants these crowds to be utterly, transcendently huge.

There's bound to be some anti-Oprah stuff out there today... James Fry, the Leadership Academy...and questions about whether she can mention her campaigning on her television show... but all these are largely irrelevant to politics.