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If Barack Obama succeeds in becoming President of the United States, a small black woman with a gift for words will have earned a place in history for helping to revitalise his flagging campaign this year.

She is not Oprah Winfrey, the daytime TV queen whose brand of stardust has been tipped by the truckload over Mr Obama in recent days.

She is Edith Childs, a 59-year-old grandmother whom he usually describes as a “little woman with a big hat”. It was Miss Childs, as she would prefer to be known, who gave him the most effective slogan of the 2008 White House race: “Fired up! Ready to go!”. It is now printed on thousands of T-shirts and banners and is used to rouse crowds previously left underwhelmed by his sometimes diffident performances.

The Democratic presidential candidate has turned an anecdote about her into the peroration of his campaign stump speech. The way Mr Obama tells it, he had promised, rashly, to swing by the city of Greenwood — far from the campaign trail usually trodden by presidential candidates — as he sought a key endorsement in the South Carolina primary.

The state votes on January 29 and he is a tight fight with Hillary Clinton for the African American support which accounts for up to half of the Democratic vote. Polls suggest he has closed the gap, or even taken the lead, in the early contests of Iowa, New Hampshire and South Carolina.

But the morning of his visit to Greenwood on June 15 did not augur well. Exhausted from campaigning, he awoke at 6am to find it was raining, he had a cold coming on and there was a bad story about him in the newspaper.

“I'm sleepy, I'm wet and I'm mad,” says Mr Obama. “And we start driving and we drive and we drive and we drive,” he says. “Finally, we get to Greenwood and, lo and behold, there are only 20 people there.” But then he heard a voice shouting out: “Fire it up! Ready to go!” Startled, he looked around to see “this little woman, about 65 years old, and she's got sort of an outfit on, she's got a church hat, a big hat”. There is usually laughter as he says: “It turns out that this woman is famous for her chant,” he says. “Everywhere she goes, she leads people in this chant.”

After a few minutes, “I'm feeling kind of fired up. I feel like I'm ready to go,” he says, explaining how “one voice can change a room” and, by extension (if not a leap of logic), “the world”. At this stage, the audience joins him in the chant and presumably then goes home happy, ready to change the world.

But neither the town nor the “little woman” herself quite match Mr Obama's description, raising questions in some quarters about why he would choose to belittle her. For instance, this former nurse is a lot younger than 65 and says, with a gold-toothed smile, “I've told him not to make that mistake again”.

She is a respected member of Greenwood City Council who talks with pride about supporting a $12 million (£6 million) new library and setting up a “crimestoppers' hotline”. And Mr Obama was “exaggerating” the tiny nature of the crowd which greeted him in June. There were at least 40 Greenwood citizens present and numbers had been strictly limited by the campaign itself. Many people were disappointed to have been left out and Miss Childs says the candidate has since promised to come back next month. “He has not apologised to me — he doesn't need to — but he should apologise to those other folk. Their feelings were hurt,” she says. “He talks of it being a 'little town' but there are 70,000 people in this county.”

Miss Childs promises to give him a tour of Greenwood, which boasts of having one of the broadest Main Streets in America. “He views it as a place from nowhere. Well, anywhere is nowhere if you haven't been there.”

Asked to perform the famous chant, she does so with a soft voice, less intense than Mr Obama's rendition, swinging her hips and making circling motions with her hands. She first heard it as a civil rights activists more than 30 years ago and says she is “honoured” it is now being used by the campaign. But there is an occasional faint air of arrogance to Mr Obama in the sneering glances this former Harvard law professor exchanges with aides when voters ask him long-winded questions, and in his attitude to Greenwood, that jars with the high principles of inclusivity he espouses.

Does she ever feel as if she is being patronised? Miss Childs frowns and replies: “I just let things like that roll over — because I don't give a care.”

She initially believed America was not ready for a black president and suggests that some in her community “still think in those old ways”. But, pointing to her skin, she says this is the only chance she will have to vote for someone who “looks like this sister” and predicts “he will be the winner”. And she wants front-row seats for his inauguration. “He owes me. I gave him my chant. It was free.”

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