An outstanding column, Steven. The point you make, that while most Americans don't consider racism per se as a divisive issue, racial issues -- privilege and assistance -- are extremely divisive, and uncomfortable issues for liberals to discuss. Any election that hinges on an issue like affirmative action (or "reparations") will go against the minority candidate.
What made Obama's speech extraordinary (and what gives me hope for his candidacy) was his willingness (eagerness?) to connect racism and affirmative action as a single issue and to attempt to emphasize the issues of privilege and prejudice in his campaign, not simply to repudiate the comments of his minister and "put the issue behind him".
It is a very risky move, and while we "liberal media elites" may applaud, we won't know the impact of the message until the people who go to church every Sunday and fear for their jobs every Monday get to vote. What Obama asked for -- a more perfect union -- has not been seriously discussed since Johnson's Great Society.