The politics of race in America has seeped into the Democratic campaign for the White House, even as candidates try to halt a bevy of allegations and insults in a country that still bears the scars of racial segregation, analysts say.

Barack Obama has been plunged anew into the fracas, after long facing media accusations of being "not black enough" while walking a fine line between appealing to black voters and trying not to alienate white voters in the process.

"Obama has made a point of minimizing and keeping his race out of the campaign," said David Bositis, a researcher at the Joint Center for Political and Economic Studies. "He doesn't specifically talk about black issues ... black voters are not Obama's base."

Meanwhile, some of the heaviest criticism has been unloaded on Hillary Clinton's campaign, which some commentators accuse of gradually attempting to paint her rival in the stereotype of a drug-using black man, coupled with hints at a Muslim background which could frighten off many voters.

Worse, some say, is the former's first lady's assertion that the aspirations of civil rights leader Dr. Martin Luther King, Jr could not have been accomplished had President Lyndon Johnson not been elected and able to enact the necessary legislation.

The 46-year-old Illinois senator and son of a white American woman and Kenyan father, who has often cited the legacies of civil rights leaders in his rousing campaign speeches, has calmly dismissed suggestions that he perhaps unjustly compared himself to former president John F. Kennedy and King.

The candidates attempted to call a truce Monday, vowing that common ground was most important.

But the reverberations of the race row have continued to pervade the White House contest as media analysts, prominent American politicians and other figures anticipated more tussles to come.

Some prominent African-Americans have attempted to come to the rescue of Clinton, whose husband Bill enjoyed significant popularity among blacks during his terms in the White House from 1993 to 2001.

"I think there's been a deliberate, systematic attempt on the part of some people in the Obama camp to really fan the flame of race and really try to distort what Senator Clinton said," according to Georgia state legislator John Lewis.

But others point to hints dropped by allies of Clinton as proof of a concerted effort to negatively portray Mr Obama, who in a published memoir, "Dreams of My Father," has acknowledged dabbling in cocaine as a youth finding his way.

The billionaire founder of the Black Entertainment Television, Bob Johnson, defended the Clintons' record on supporting black issues when Obama "was doing something in the neighbourhood," hinting at his past drug use.
A top Clinton staffer had brought up the same topic last month, which led to his resignation and a flurry of apologies from the 60-year-old New York senator's campaign.

Johnson even accused Mr Obama of trying to blur his racial distinction so much that he had been acting like a "guy that says I want to be a reasonable, likeable Sidney Poitier 'Guess Who's Coming to Dinner.'"

The 1967 film is seen as emblematic of an era when black men had to erase as much of their ethnic and cultural identity as possible in order to be accepted by whites.

For political science professor Larry Sabato, Johnson's intervention was a sign of Mr Obama's failure to convince black voters -- who polls suggest prefer Clinton two-to-one over Mr Obama -- that he is their candidate.

"He must win a large majority of the African-American vote," Mr Sabato said, pointing out the difficulties Mr Obama faces in appealing to both white and black Democratic voters. "African-Americans have wondered whether he could win."

Mr Bositis recalled that "Obama's strongest support has been among whites, especially more affluent whites ... younger people, people looking for a new generation of leadership, suburban whites."

But historian David Greenberg of Rutgers University warned that that appeal -- a phenomenon used to describe Obama's sweep of the predominantly white and rural Iowa caucuses earlier this month sometimes called Obamania -- may fall flat.

"Obamamania -- the phenomenon, not the man -- leads us to believe that if only we vote for an African-American, an avatar of 'change' and healing, we can slough off the burdens of our past," he said.