St Paul, Minnesota - Augustus Shaw's mother marched with civil rights leader Martin Luther King Jr, and she doesn't understand why her son supports Republican presidential nominee John McCain over Democrat Barack Obama.

But Shaw cites King's most famous oratory, the so-called "I have a dream" speech to a massive rally in Washington, to answer why he disagrees with the overwhelming majority of African-Americans supporting Barack Obama's historic bid to become the first black president.

King, a Southern preacher, described the hope for his children to someday "live in a nation where they will not be judged by the colour of their skin, but by the content of their character."

"That was Martin Luther King's dream," Shaw said. "I'm going to judge these presidential candidates by their characters, not the color of their skin. ... When I remind Mom of that line in his speech, she pauses."

Shaw, 35, an Arizona delegate to the Republican National Convention, is an attorney and US Navy veteran who enlisted during the 1991 Gulf War. He called Obama - who accepted the centre-left Democratic presidential nomination on August 28, the 45th anniversary of King's speech - "very articulate, smart. He loves his country."

But McCain, a prisoner of war during the Vietnam War with 26 years in Congress "has the best life experience to lead," Shaw said.

Brian Summers, 36, a Republican strategist and delegate from the US capital of Washington, has been a staff worker on past Republican presidential campaigns. He said he disagrees even with his wife about politics, calling himself the "white sheep" of the family.

"I'm an African-American, Southern conservative man. I can tell you: bring it on, Democrats," he said. "We will meet you anywhere, Obama."

As a native of North Carolina, where his family grew tobacco, Summers recalled both "the history of the Republican Party," founded in 1854 by anti-slavery activists, and the Democratic legacy as the party of segregation in the South until the 1960s.

He cited more recent grievances as a farming family, too. "It was Democrats that imposed taxes, made it hard to earn a living," Summers said.

He acknowledged that Obama has made history as the first African- American major-party presidential nominee. "Hats off," he said. "I applaud him for living the American dream."

But Obama "forgot to get the rest of the lesson" about America, Summers said, that every American is an individual, rather than a member of a group in identity politics.

His only regret toward Obama is that "part of me wishes it had been the Republicans" to nominate the first African-American to a national office.

Shaw, the Arizona lawyer, voiced respect for Obama and his achievements.

"Barack is a great man. He has a lot to offer this country," Shaw said. "I just feel he's not the best qualified candidate."

Shaw insisted that he has "no mixed feelings" in supporting McCain. "I'm an American," he said, rejecting race as a political motivation.

Laughing, he added: "But Barack Obama will get 90 per cent of the African-American vote." (dpa)