Forty years to the day after the assassination of Martin Luther King in a racially-motivated attack, the legacy of the civil rights leader is once again at the forefront of American politics.

Both Hillary Clinton and John McCain were today to attend memorial events in Memphis, where Dr King was shot dead in 1968, hoping to win over black voters supporting Barack Obama in his bid to become the first African-American president of the United States.

Mrs Clinton in particular needs to mend fences with the black community amid suggestions that her campaign has repeatedly played the race card in its attempt to destroy Mr Obama’s candidacy.

Both she and Mr McCain, the presumptive Republican nominee, are expected to give speeches and attend an NBC News event to discuss Dr King’s role in ending segregation.

However Mr Obama will mark the anniversary in North Dakota, where he is to address the state’s Democratic convention.

The former First Lady was first accused of raising race as a campaign issue after her husband, Bill Clinton, appeared to dismiss Mr Obama’s win in January’s South Carolina primary as unimportant because it had a large African-American population who would automatically vote along racial lines.

Mrs Clinton then exacerbated the issue when she made comments viewed as denigrating Dr King’s role in ending segregation, attributing race equality and desegration laws instead to President Lyndon B. Johnson.

Though the Clintons insisted their comments had been misinterpreted - in some cases deliberately - a number of successive incidents compounded the perception that they were playing racial politics. Her campaign was accused of deliberately leaking a photo of Mr Obama dressed in a traditional Somali costume and casting doubt upon his religion, while Geraldine Ferraro, a former Congresswoman, was forced to resign from Mrs Clinton’s finance committee after she said that Mr Obama was only winning the contest because he was black.

Mr McCain too has some work to do to improve his standing among the black community. While he has largely stayed out of the raging race debate, he skipped a Republican campaign debate last September that focused on African-American issues, while his vote against creating a federal holiday marking Dr King’s birthday has been cited repeatedly by the Democrats.

However he appeared to express regret for that vote this week, telling reporters that he had “learned that this individual was a transcendent figure in American history”, and deserved to be honoured.

He is to speak to the Southern Christian Leadership Conference at a civil rights museum built at the old Lorraine Motel where Dr King was killed.

Mr Obama’s speech will also be watched closely, though in his case it is certain sections of the white community that he hopes to win over. He saw his support ebb following tevelations about controversial rhetoric in some sermons given by his former pastor, the Reverend Jeremiah Wright. Though he has recovered in the polls following a well-received speech on race relations in America, some voters, particularly white blue collar males, have yet to be convinced.

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