It sure wasn't because she wasn't qualified enough. Or strong enough. Or smart enough. Or determined enough. Or caring enough.
In the end, it was because she wasn't woman enough. It's because she didn't rely on the secret weapon that all women call on in the toughest of times: our intuition.
Especially when we're struggling to find our own voice.
On Saturday, Hillary Rodham Clinton finally conceded, deferring her dream of becoming our first woman president and leaving behind 18 million supporters, mostly women, who also saw their dreams denied - this time.
Understandably, the hurt, bitterness and anger linger. So much so that some supporters are threatening to vote against their best interests - and their daughters' best interests - or, worse yet, not vote at all.
"Sexism is rampant and politically acceptable," one woman reader wrote.
"I'm thinking of writing Hillary in," said another aggrieved e-mailer, willing to waste her precious vote to make a moot point.
While some may bolt to John McCain, the maverick standard-bearer for women's rights who voted against equal pay for women, the Family and Medical Leave Act, and a woman's right to choose, I'm not buying the threat.
Because our best qualities as women will win.
Reflection is one of them.
Like racism, sexism is in force, of course. A woman ran for the highest and most powerful office in the land and sought to be a first.
And as Hillary fought her way to history, she applied all the lessons that we're taught as girls living in a man's world: Be tough, work harder, don't quit, and - whatever you do - don't cry.
But along the way, she also forgot the best lessons, the ones that universally define us as women, the ones our mothers taught us - and that we only fully understand when we get to be about Hillary's age.
Don't change who you are, don't let a man weigh you down, don't be afraid to admit when you're wrong, tell the truth, be gracious - win or lose.
It's ironic that as she tried harder to compete by men's rules - tough talk, strategic game play, changing personas, and the rules to gain an advantage, not initially embracing her symbolic standing as a woman with the depth she did at the end - Barack Obama beat her at a woman's game.
Following his intuition. Building a campaign around hope, unity, trust and change, actually believing that people would set aside their differences to strengthen the family.
All the strength we thought a woman would bring to the White House.
Which is why some women, who still admire Hillary as the ultimate ceiling-shatterer, aren't conflicted about joining the 18 million Obama supporters, mostly women, who connected with his uniquely feminine approach long ago.
Lois Geehr, 75, says Obama resonated with her way back in '04, when he first uttered "hope" at the Democratic National Convention.
"When I heard him, I said, 'That man is headed for the presidency,' " says the retired copy editor, who lives in North Wales.
She just didn't think his time would come in '08 - and collide head-on with Hillary's.
A sign-carrying libber, who supported
Roe v. Wade
way back in the '70s, Geehr said that for her, not voting for Hillary would be almost sacrilegious.
But now that Hillary has conceded, "I will be voting Obama, believe you me," she said. "More than anything, I wanted Hillary to prove she could do the job, and I think she did that. Her accomplishment for women was amazing and hoped for."
"At the end, she finally accepted the fact that she was a woman, and not as a presidential candidate who happened to be a woman," sighed Patricia Ripoll, 61, a Hillary admirer since the '70s, when a young lawyer named Hillary Rodham advised the Children's Defense Fund.
She says she'll enthusiastically vote for Obama, who she says has a gift for oratory that "can raise the dead."
Still, the teacher admits it was wrenching to watch Clinton's speech Saturday.
"There was an incredible sadness. It was like attending a funeral. It was the end of the road for this woman who is so incredible," Ripoll said.
Almost as an afterthought, she added: "Obama won. But Hillary didn't lose."