How many Americans watching the elegant Michelle Obama and her pretty daughters on stage at the Democratic Convention in Denver saw a poised professional woman, and how many only really registered her colour? Almost every item of coverage of Michelle and Barack Obama is preceded by the phrase "the first African-American to "

Strange, isn't it, that the presidential nominee with his white mother and Kenyan father is automatically filed as "black" although his genetic inheritance gives him equal claim to either race?

He should be, may yet be, celebrated as the most potent example of how melting pot America produces people of extraordinary talent. His audiences on the trail certainly suggest that's how many young Americans view him; an icon of what we somewhat prematurely call the post racial age. Race and ethnicity, as we witness all too often, are still provocative factors in the most needless and bloody conflicts in every one of the world's continents. And it is most certainly an issue in the American election, although political correctness often supplies it with camouflage.

People trying to articulate their hesitancy about the one-term senator from Illinois will cite every other factor except the dirty little secret of their instinctive racism. Obama himself has been reluctant to confront this most stubborn of barriers to his universal acceptance despite the fact that when it leapt up and bit him at the time his erstwhile pastor did his bit to stir up racial disharmony, Obama made one of his most thoughtful speeches of the year; an eloquent hymn to a wholly United States of America.

It's a tough message to convey, for we are all of us to some extent prisoners of our own cultural hinterland. Watching Michelle deliver her conference speech, I found myself trying hard to remember who she reminded me of, until it finally dawned it was Jane Fonda at the same age. Did that information take so long to retrieve from my memory banks because it was the middle of the night, or because her brown skin had me filing her in a separate compartment? One of the last sessions I chaired at the Edinburgh International Book Festival featured the amiable, much talented Hardeep Singh Kohli; a mobile advert for multicultural Scotland at its best. Yet Hardeep, dyed in the wool Glaswegian as he is, recalls an incident in his childhood which was to alert him to the fact that in some quarters, he would always be what his brother Sanjeev once described as "a coconut, brown outside, white in."

He was with a bunch of kids going back to one of their homes to try out the latest craze for home-made ice lollies. The mother barred his way: "Youse can all come in but not him." Coming as he did from a family of aspirational and cosmopolitan Indians, he reported the incident to his mum, but utterly rejected her advice not to "rock the boat."

After all, as he pointed out, for that young lad in 1970s Bishopbriggs, "Glasgow was the beginning, middle and end of my reality." He now describes that childhood as a cultural car crash between his parents' values and the ridicule he encountered in the playground. The fact of being sent to a Catholic secondary meant he got to double up in terms of being a minority. The book he has written is ostensibly a culinary romp round India cooking and force-feeding a succession of bemused locals a succession of improbably British dishes (though getting the gear for stovies defeated him.) But in essence it's also a journey of self-discovery, trying to resolve the ambivalence inherent in being a proud Scottish son of proud Indian and Kenyan Asian parents.

A man who still exults in his Glaswegian roots despite being routinely abused as "a fat kid with glasses and a turban". And a man who also imbibed the cultural importance of food and hospitality at his mother's and grandmother's knees. A seminal moment came in the Punjab from where his father hailed, and he shopped for yet more of his trademark gaudy turbans where his grandfather had once bought his. "What could be more Punjabi than a Sikh man buying turbans in the Punjab," he ruminates. And, in that moment, acknowledges that he is, nevertheless, "more British than he ever knew."

Obama, if he becomes President Obama, will take into the oval office echoes of a childhood in Indonesia and Hawaii, of studying in overwhelmingly white Harvard, as his father did before him, then exercising his legal skills in largely black poor communities in Chicago. That rich mixture of experience has produced a man self-evidently comfortable in his own skin.

Let's hope the American electorate has the maturity to find its colour incidental.