White House hopeful Bill Richardson's friendship with Ernesto Miranda began when the boy in tattered clothing, carrying two buckets, knocked on the door of the Richardson family's sprawling Mexico City estate to ask for water.

"Billy" asked him to stay and play.

Every afternoon after that, Ernesto would drop his schoolbooks off at his family's hovel of volcanic rock, corrugated metal and cardboard, then race to the nearby hacienda to stage cowboy shootouts in the flowery gardens or bat around baseballs with the son of a wealthy American banker.

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Throughout the 1950s, Ernesto and Billy shared their separate worlds, straddling Mexico's deep divide between rich and poor. It was a profound, formative experience for the future Democratic presidential contender, whose father was an international banker from Boston and whose mother was Mexican.

"My father was very proud of his American son, and my mother was very proud of her Mexican son. Their pride was passed down to me, and I grew up honoring both the United States and Mexico," Richardson wrote in his biography, "Between Worlds: The Making of an American Life."

The Democratic candidate did not respond to The Associated Press' request seeking comment on the friendship, but his campaign spokesman, Pahl Shipley, confirmed that Ernesto was a childhood friend.

Billy's father, William Blaine Richardson, the Mexico City manager of First National City Bank of New York — today Citibank — sent his Mexican wife, Maria Luisa Collada, to give birth in Pasadena, Calif., preventing any questions about his son's U.S. citizenship.

"Billy" lived in Mexico until the age of 13, when he left his family to attend school in the United States. By then, his childhood had already shaped him personally and politically.

It was Ernesto who introduced his wealthy friend to other children from the "lost city," the slum that surrounded the Richardson family's walled compound. These neighborhood children were welcome inside the estate, spending afternoons watching television or viewing movies projected onto a sheet that Billy's mother hung on a wall.

"The poorest kids would go to his house," Ernesto, now 63, recalled in an interview with The Associated Press. "He made no distinction between us."

Billy's father turned a corn field on their land into a baseball diamond, where the boys dubbed themselves "Los Yankees de San Francisco," after Billy's favorite U.S. team and the neighborhood where they lived.

The Richardson family later paid the fees so the best players, including Ernesto, could join Mexico City's little league, breaking the city's class barrier.

"After seeing us, the managers would say to Billy's father, 'Hey, bring me some more of these kids. They're tough, not like some of my other players who are crybabies,"' Ernesto said.

Ernesto's brother Felix, 56, said Billy had a fighting spirit.

"I remember one day when he lost a game, he cried," Felix said. "He never lost. He always was looking to triumph."

Billy also made sure his neighborhood friends were treated with respect. At times, Ernesto recalled, Billy's wealthy friends would ask, "Why are you hanging out with those dirty kids? You'll catch something from them."

"Billy would say, 'You guys are the ones who will give me something. These are my friends,"' Ernesto said.

Ernesto said he regrets not taking advantage of some of the opportunities the Richardson family gave him, including tuition for a private elementary school. He dropped out to earn money delivering tortillas.

Later, when his girlfriend became pregnant, the Richardson family paid for him to get married at a colonial church normally reserved for elite weddings, he said. Billy's father also let Ernesto and his bride live at the family's vacation home for five years.

"They always wanted me to make something more of myself, but I was foolish," he said.

Ernesto ended up delivering tortillas for more than 40 years until he was hit by a car last year. The accident crushed his hip as he rode a bicycle loaded with 100 pounds of tortillas. Now he walks with a cane and spends his days in a graffiti-covered, cinderblock house on a small plot of land that includes the homes of his five children, three grandchildren and four of his five siblings.

The land where both boys grew up is now an upper-middle-class neighborhood, and Ernesto Miranda lost contact with Bill Richardson decades ago. But he still has a photo of them together at Richardson's first communion, and he has followed his friend's diplomatic and political career, watching in awe as Richardson negotiated with Saddam Hussein, Fidel Castro and the North Koreans. Richardson was elected governor of New Mexico in 2002 and 2006.

Ernesto hopes they'll see each other again some day.

"To sit and talk to Billy would be like going to Disneyland for me," he said.