Obama breaks down historic racial barrier

But the nominee – the son of a black Kenyan father and a white American mother – was also to talk about the US’s many challenges, from health care to international threats, campaign manager David Plouffe said on ABC’s Good Morning America news show.

His acceptance of the Democratic nomination comes on the 45th anniversary of the Rev King’s August 28, 1963, “I Have a Dream” speech, an exhortation about the frustration of blacks at a time when African Americans in many southern states were denied their voting rights more than 90 years after the federal government guaranteed them that right.

Given America’s tortured racial history – Obama was just 2 when King delivered his speech – the candidate’s nomination is a gamble for the Democrats in the November 4 election as they work to wrest the White House from the Republicans and their candidate McCain, a veteran Arizona senator and Vietnam war hero who turns 72 on Friday.