With her family watching on, Hillary Clinton gave her backing to Barack Obama and withdrew from the race to become US president.
In an emotional yet gracious speech, the former First Lady thanked all those who had helped her and given her their vote. Now, she said, it was time to take "our energy, our passion" and elect Democrat Mr Obama.
Hundreds of supporters queued for hours outside the National Building Museum in Washington to hear Mrs Clinton. Several cried as the 60-year-old told them of her decision.
Despite her sad news, the Senator was upbeat and happy of what she had achieved. "Children today will grow up taking for granted that an African-American or a woman can, yes, become the president of the United States," she declared.
And, she added, she had no regrets. "Life is too short, time is too precious and the stakes are too high to dwell on what might have been," she told the packed hall. "We have to work together for what still can be."
Her former rival said he was "thrilled and honoured" to have Mrs Clinton's support.
"She shattered barriers on behalf of my daughters and women everywhere, who now know that there are no limits to their dreams," he added.