The line is gracious, but brief and guarded. Mr. Obama rarely dwells on race with his visitors or nearly anyone else. In interviews with dozens of black advisers, friends, donors and allies, few said they had ever heard Mr. Obama muse on the experience of being the first black president of the United States, a role in which every day he renders what was once extraordinary almost ordinary. 

But his seeming ease belies the anxiety and emotion that advisers say he brings to his historic position: pride in what he has accomplished, determination to acquit himself well and intense frustration. Mr. Obama is balancing two deeply held impulses: a belief in universal politics not based on race and an embrace of black life and its challenges. 

Vigilant about not creating racial flash points, the president is private and wary on the subject, and his aides carefully orchestrate White House appearances by black luminaries and displays of black culture. Those close to Mr. Obama say he grows irritated at being misunderstood — not just by opponents who insinuate that he caters to African-Americans, but also by black lawmakers and intellectuals who fault him for not making his presidency an all-out assault on racial disparity. 

“Tragically, it seems the president feels boxed in by his blackness,” the radio and television host Tavis Smiley wrote in an e-mail. “It has, at times, been painful to watch this particular president’s calibrated, cautious and sometimes callous treatment of his most loyal constituency,” he continued, adding that “African-Americans will have lost ground in the Obama era.” 

Such criticism leaves the president feeling resentful and betrayed, aides said, by those he believes should be his allies. The accusations are “an assault on his being,” said David Axelrod, his chief strategist — not to mention a discomfiting twist in a re-election fight in which the turnout of black voters, who express overwhelming loyalty to the president but also some disappointment, could sway the result. 

But like an actor originating a role on Broadway, Mr. Obama has been performing a part that no one else has ever played, and close observers say they can see him becoming as assured on race in public as he is in private conversation. In 2009, the new president’s statement on the arrest of a black Harvard professor by a white police officer set off days of negative headlines; in 2012, he gave a commanding but tender lament over the killing of a black teenager, Trayvon Martin, by a white man. 

“As he’s gotten more comfortable being president, he’s gotten more comfortable being him,” said Brian Mathis, an Obama fund-raiser. 

Asked when they could sense that shift, several advisers and friends mentioned the waning hours of Mr. Obama’s birthday party in the summer of 2011. As the hour grew late, many of the white guests left, and the music grew “blacker and blacker,” as the comedian Chris Rock later told an audience. Watching African-American entertainers and sports stars do the Dougie to celebrate a black president in a house built by slaves, Mr. Rock said, “I felt like I died and went to black heaven.” 

The president, guests recalled, seemed free of calibration or inhibition. He danced with relative abandon, other guests ribbing him about his moves, everyone swaying to Stevie Wonder under a portrait of George Washington. 

Trying to Avoid a Wedge
In the White House, Mr. Obama has relied on a long-term strategy on race and politics that he has been refining throughout his career.As far back as 1995, former colleagues at the University of Chicago remember him talking about moving away from the old politics of grievance and using common economic interests to bind diverse coalitions. “He argued that if political action and political speeches are tailored solely to white audiences, minorities will withdraw, just as whites often recoil when political action and speeches are targeted to racial minority audiences,” recalled William Julius Wilson, now a sociologist at Harvard. 

Mr. Wilson had turned the world of social policy on its head by arguing that class was becoming more determinative than race in America and pointing out that race-specific remedies were less politically feasible than economic policies that benefited a broad range of people. The young politician absorbed Mr. Wilson’s ideas, which matched his own experience as a community organizer and a person whose own life did not fit neat racial categories. 

Mr. Obama now presides over a White House that constantly projects cross-racial unity. When discussing in interviews what image the Obamas want to project, aides use one word more than any other: “inclusive.” Concerts of Motown and civil-rights-era songs have been stocked with musicians of many races, and in introducing them, the president emphasizes how the melodies brought disparate Americans together. Though the Memphis sanitation workers were involved in a shattering moment of the civil rights struggle — Dr. King was assassinated after going to support their strike — they were invited to the White House for a labor event, not a race-oriented one. 

Many of the president’s most critical domestic policy decisions have disproportionately benefited African-Americans: stimulus money that kept public sector workers employed, education grants to help underperforming schools and a health care overhaul that will cover tens of millions of uninsured Americans. But he invariably frames those as policies intended to help Americans of all backgrounds. 

“If you really want to get something done, you can’t put it in a way that will kill it before it gets going,” Mr. Obama said in one meeting, according to the Rev. Al Sharpton. “We have to deal with the specific problems of different groups — blacks, women, gays and lesbians, immigrants — in a way that doesn’t allow people to put these wedges in,” Mr. Sharpton recalled the president saying in another. 

That approach, along with the memories of the toxic campaign battles over Mr. Obama’s former pastor, the Rev. Jeremiah A. Wright Jr., has resulted in a White House that often appears to tiptoe around race. 

Debra Lee, the chairman and chief executive of Black Entertainment Television, requested interviews with the Obamas in 2009, but press aides told her that they did not want the first couple on BET in the first six months of the administration, she said in an interview. (They appeared later.) 

“There was all this caution and concern because we were in the midst of a great American experiment,” one former aide said. Another aide remembered palpable nervousness about the artwork the Obamas chose for their private quarters in the White House, including some with race-specific messages. 

In private, White House aides frequently dissect the racial dynamics of the presidency, asking whether Representative Joe Wilson, Republican of South Carolina, would have yelled “You lie!” at a white president during an address to Congress or what Tea Party posters saying “Take Back Our Country” really mean. Michelle Obama, often called the glue in her husband’s relationship with black voters, sometimes remarks publicly or privately about the pressures of being the first black first lady. 

Her husband is more circumspect, particularly on the question of whether some of his opposition is fueled by race. Aides say the president is well aware that some voters say they will never be comfortable with him, as well as the occasional flashes of racism on the campaign trail, such as the “Put the White Back in the White House” T-shirt spotted at a recent Mitt Romney rally. But they also say he is disciplined about not reacting because doing so could easily backfire. 

“The president knows that some people may choose to be divided by differences — race, gender, religion — but his focus is on bringing people together,” Valerie Jarrett, a senior adviser, wrote in an e-mail. 

Even when Newt Gingrich called him a “food stamp president” during the Republican primaries, the most the president did was shoot confidants a meaningful look — “the way he will cock his head, an exaggerated smile, like ‘I’m not saying but I’m saying,’ ” one campaign adviser said.
To blacks who accuse him of not being aggressive on race, Mr. Obama has a reply: “I’m not the president of black America,” he has said. “I’m the president of the United States of America.” 

That statement “makes me want to vomit,” Cornel West, an activist and Union Theological Seminary professor, said in an interview. “Did you say that to the business round table?” he asked rhetorically. “Do you say that to Aipac?” he said, referring to a pro-Israel lobbying group.
Members of the Congressional Black Caucus, with whom the president has a contentious relationship, have echoed the charges that Mr. Obama is insufficiently attentive to African-Americans, even threatening at times to sandbag his agenda. 

Even some of Mr. Obama’s black supporters privately express the same anxiety, in more muted form. At the first meeting of his top campaign donors last year, some black donors were dismayed when officials handed out cards with talking points on the administration’s achievements for various groups — women, Jews, gays and lesbians — and there was no card for African-Americans. 

The accusation that Mr. Obama does not care about black suffering appears to carry little weight with the African-American public, and yet it tears at the president, say aides, friends and supporters. 

After a 2010 speech at the National Urban League, he approached Mr. West. “He just came at me tooth and nail,” Mr. West said. “Are you saying I’m not a progressive?” Mr. West recalled the president asking. 

Mellody Hobson, an Obama fund-raiser, explained why the accusation was painful.
“You expect your family to give you the benefit of the doubt,” she said. 

Out to Change Stereotypes
 
Shortly before his 2009 inauguration, Barack Obama took his family to see the Lincoln Memorial. “First African-American president, better be good,” a 10-year-old Malia Obama told her father, who repeated the story later, a rare acknowledgment of the symbolic shadow he casts. 

For all of Mr. Obama’s caution, he is on a mission: to change stereotypes of African-Americans, aides and friends say. Six years ago, he told his wife and a roomful of aides that he wanted to run for the White House to change children’s perceptions of what was possible. He had other ambitions for the presidency, of course, but he was also embarking on an experiment in which the Obamas would put themselves and their children on the line to help erase centuries of negative views. 

While Mr. Obama resists being the president of black America, he does want to change black America, aides say — to break apart long-held beliefs about what African-Americans can and cannot do. The president, who appointed Lisa P. Jackson and Charles F. Bolden Jr. as the heads of the Environmental Protection Agency and NASA, wants to encourage black achievement in science and engineering, even urging black ministers to preach about the need to study those subjects. 

Mr. Obama knows that the next presidential candidate of color may be judged by his own performance, added Charles J. Ogletree, a Harvard law professor. And Mr. Obama’s desire to win re-election in part because he is the first black president is “so implicit it’s just like breathing,” one White House adviser said. 

On rare occasions, Mr. Obama allows others a glimpse of the history, expectations and hope he carries with him. At the funeral of the civil rights leader Dorothy Height in 2010, he wept openly. Again and again, those close to him say, Mr. Obama is moved by the grace with which other blacks who broke the color barrier behaved under pressure. 

When Ruby Bridges Hall went to see the famous Norman Rockwell portrait of her marching into school, which Mr. Obama had hung just outside the Oval Office, the president opened up a bit. The painting shows a 6-year-old Ms. Hall in an immaculate white dress walking calmly into school, a hurled tomato and a racial slur on the wall behind her. 

The president asked Ms. Hall, now 58, how she summoned up such courage at that age and said he sometimes found his daughters staring at the portrait. “I really think they see themselves in this little girl,” he said, according to an interview with Ms. Hall. 

“Doing the work we do, it gets really lonely,” Ms. Hall said. “I felt like we understood each other because we belong to the same club.”