We may never know what did it: whether it was the $8m advance or just sheer enthusiasm. But as 2pm approached, Hillary Rodham Clinton was still hard at work, seated in the science fiction/fantasy section of a mid-town New York bookstore, furiously signing copies of her memoir, Living History. That was almost two hours longer than the incandescently yellow pant-suited senator had intended for this, the launch of her worldwide book-signing tour.
And according to her profoundly grateful publicist, the result was at least 1,200 purchasers more than expected on a day on which 40,000 bought into her tale - a non-fiction record in the United States, beating the numbers who lined up more than a decade ago at the same Fifth Avenue bookstore for Margaret Thatcher and Ronald Reagan put together.
By the second hour, Hillary was really getting into it. After acknowledging that Bill had helped draft the opus - including, presumably, the hellish confession about his "inappropriate intimacy" with Monica - and denying that she had ever two-timed her husband, there was no stopping the former first lady. By the time I showed up, swept in on a whim through security guards who, incredibly, had dropped any form of check-and-control, she was signing 13 a minute and still going strong.
"Thank you so much for coming!" the author cried, all goggle-eyed, at each five-second interaction.
"Thank you," she said firmly, politely putting paid to the desire for a dedication from the young woman next in line. "How are you? Gosh, it's good to see you again," she continued, the banter flowing with the ink. "I just love that lilac blue shirt. Where did you get that?! Wow! This is a really fast signature, I mean really fast signature . . . Alison, Mary, Steve," she called, beckoning to a posse of black-bedecked aides, "keep them coming!"
Hillary Clinton may be as difficult to read now as she was before the release of this singularly unrevealing 526-page blockbuster, described by one critic as having "the over-processed taste of a stump speech". But even if it means emerging horribly weak-wristed, she'll go out of her way to work a floor. Not that the assembled journalists were willing to give her much of their time.
For most, Living History is simply living proof that Hillary is not only looking to New Yorkers for re-election to the Senate, but is now bent on running for the presidency in 2008 or 2012. So, with the exception of the New York Post, which takes its Hillary-bashing seriously, the media had left long before the book- signing was over.
Even the Washington Post, the subsequent bearer of several pages unfavourably comparing the formidably bright US senator with Laura Bush, appeared to have made up its mind beforehand. Its reporter was nowhere to be seen.
"What you have to realise," snarled the columnist from the New York Post, "is that this is very creepy. But if you're from the Guardian, you probably think that we're right-wing trash, and we'll think you're a bunch of reds, so we're sworn enemies anyway."
"If you say so," I said. "So you think this is it, she's going to run for president?" "Yeah," she retorted, shaking her head. "They want to see a White House sequel: President Clinton II. It's surreal." Living History may well illuminate the insincerity of the political memoir as an art form. But in promoting it, the senator has proved, quite sincerely, that she has plenty of ambition left.
Helena Smith is a foreign correspondent for the Guardian