WASHINGTON (Map, News) - Sen. Barack Obama, the only major black candidate in the 2008 presidential race, has spent much of his life anguishing over his mixed-race heritage and self-described “racial obsessions.”

Descended from a white American mother and black Kenyan father, the Illinois Democrat once wrote: “He was black as pitch, my mother white as milk.”

In his first memoir, “Dreams from My Father,” Obama observed that when people discover his mixed-race heritage, they make assumptions about “the mixed blood, the divided soul, the ghostly image of the tragic mulatto trapped between two worlds.”

Indeed, Obama acknowledges feeling tormented for much of his life by “the constant, crippling fear that I didn't belong somehow, that unless I dodged and hid and pretended to be something I wasn't, I would forever remain an outsider, with the rest of the world, black and white, always standing in judgment.”

Obama's views on race are certain to be an issue in the upcoming presidential campaign, according to Princeton University professor Melissa Harris-Lacewell, who specializes in African-American politics.

“There’s no question that race and all the permutations that it’s going to take for Obama are going to be central issues,” she predicted.

Although Obama was raised by his mother, he identified more closely with the race of his father, who left the family when Obama was 2.

“I ceased to advertise my mother's race at the age of 12 or 13, when I began to suspect that by doing so I was ingratiating myself to whites,” he wrote.

Yet, even through high school, he continued to vacillate between the twin strands of his racial identity.

“I learned to slip back and forth between my black and white worlds,” he wrote in “Dreams.” “One of those tricks I had learned: People were satisfied so long as you were courteous and smiled and made no sudden moves. They were more than satisfied; they were relieved — such a pleasant surprise to find a well-mannered young black man who didn't seem angry all the time.”

Although Obama spent various portions of his youth living with his white maternal grandfather and Indonesian stepfather, he vowed that he would “never emulate white men and brown men whose fates didn't speak to my own. It was into my father’s image, the black man, son of Africa, that I’d packed all the attributes I sought in myself, the attributes of Martin and Malcolm, DuBois and Mandela.”

Obama wrote that in high school, he and a black friend would sometimes speak disparagingly “about white folks this or white folks that, and I would suddenly remember my mother's smile, and the words that I spoke would seem awkward and false.”

As a result, he concluded that “certain whites could be excluded from the general category of our distrust.”

Donna Brazile, who managed former Vice President Al Gore’s presidential campaign in 2000, said Obama's feelings of distrust toward most whites and doubts about himself are fairly typical for black Americans.

“He was a young man trying to discover, trying to accept, trying to come to grips with his background,” she explained. “In the process, he had to really make some statements that are hurtful, maybe. But I think they're more insightful than anything.”

During college, Obama disapproved of what he called other “half-breeds” who gravitated toward whites instead of blacks. And yet after college, he once fell in love with a white woman, only to push her away when he concluded he would have to assimilate into her world, not the other way around. He later married a black woman.

Such candid racial revelations abound in “Dreams,” which was first published in 1995, when Obama was 34 and not yet in politics. By the time he ran for his Senate seat in 2004, he observed of that first memoir: “Certain passages have proven to be inconvenient politically.”

Thus, in his second memoir, “The Audacity of Hope,” which was published last year, Obama adopted a more conciliatory, even upbeat tone when discussing race. Noting his multiracial family, he wrote in the new book: “I’ve never had the option of restricting my loyalties on the basis of race, or measuring my worth on the basis of tribe.”

This appears to contradict certain passages in his first memoir, including a description of black student life at Occidental College in Los Angeles.

“There were enough of us on campus to constitute a tribe, and when it came to hanging out many of us chose to function like a tribe, staying close together, traveling in packs,” he wrote. “It remained necessary to prove which side you were on, to show your loyalty to the black masses, to strike out and name names.”

He added: “To avoid being mistaken for a sellout, I chose my friends carefully. The more politically active black students. The foreign students. The Chicanos. The Marxist professors and structural feminists.”

Obama said he and other blacks were careful not to second-guess their own racial identity in front of whites.

“To admit our doubt and confusion to whites, to open up our psyches to general examination by those who had caused so much of the damage in the first place, seemed ludicrous, itself an expression of self-hatred,” he wrote.

After his sophomore year, Obama transferred to Columbia University. Later, looking back on his years in New York City, he recalled: “I had grown accustomed, everywhere, to suspicions between the races.”

His pessimism about race relations seemed to pervade his worldview.

“The emotion between the races could never be pure,” he laments in “Dreams.” “Even love was tarnished by the desire to find in the other some element that was missing in ourselves. Whether we sought out our demons or salvation, the other race would always remain just that: menacing, alien, and apart.”

After graduating from college, Obama eventually went to Chicago to interview for a job as a community organizer. His racial attitudes came into play as he sized up the man who would become his boss.

“There was something about him that made me wary,” Obama wrote. “A little too sure of himself, maybe. And white.”

Harris-Lacewell said such expressions of distrust toward whites will not hurt Obama in the Democratic presidential primaries, which are dominated by liberal voters.

“To win the Democratic nomination, he's got to get a part of the progressive, anti-war, white folks,” she said. “And those white folks tend to be suspicious of any black person who wouldn’t be suspicious of white people.”

Such liberals would have little basis for suspicion after reading some of Obama’s conclusions about the white race, which he once described as “that ghostly figure that haunted black dreams.”

“That hate hadn't gone away,” he wrote, blaming “white people — some cruel, some ignorant, sometimes a single face, sometimes just a faceless image of a system claiming power over our lives.”

Obama’s racial suspicions were not always limited to whites. For example, after making his first visit to Kenya, he wrote of being disappointed to learn that his paternal grandfather had been a servant to rich whites.

He wrote in “Dreams” that the revelation caused “ugly words to flash across my mind. Uncle Tom. Collaborator. House nigger.”

Such blunt and provocative observations about race are largely absent from Obama’s second memoir.

“I have witnessed a profound shift in race relations in my lifetime,” he wrote in “Audacity.” “I insist that things have gotten better.”

An adolescent confrontation

Barack Obama recalls punching out the “first boy” who “called me a coon” in seventh grade.

“I gave him a bloody nose,” Obama wrote in his first memoir, “Dreams from My Father.”

“Why’dya do that?” the boy said through “tears of surprise,” according to Obama.

It was not the first time young Obama would be subjected to racial slurs. He recalled an assistant basketball coach in high school referring to a group of black men as “niggers.”

“I told him — with a fury that surprised even me — to shut up,” Obama wrote.

“There are black people, and there are niggers,” the coach explained, according to Obama. “Those guys were niggers.”

Obama answered with contempt.

“'There are white folks and then there are ignorant motherf---ers like you,’ I had finally told the coach before walking off the court,” he wrote.

More from Bill Sammon's series:

The 5 most important things you need to know about...

Barack Obama

• Can a past of Islam change the path to president?
• 'Trapped between two worlds'
• 'The Obama position on the war'
• Perception vs. reality
• The power of positive press