However, measured intelligence can also change over time within a single race, depending on the external environment. I can't find it now, but recently saw an article pointing out that the average IQ of students from one of the Scandinavian countries (Denmark?) had increased measurably over the last 50 years. Like everything else, intelligence has both biological and societal components. I certainly don't know enough about intelligence to comment with confidence on its biological bases and how immutable (or mutable) they are, but as long as there is a societal component, then I see no inherent moral problem in trying to provide disadvantaged racial groups with the same favorable milieu that other groups have already profited from.

(And, for that matter, I think the actual harm suffered to white people by affirmative action on behalf of other groups is probably fairly small. There might be a zero-sum calculation about a specific job or specific slot at a college, but whites aren't being systematically shut out of every opportunity they might have. There's also a difference between promoting people who are blatantly unqualified for the positions they're given because of their race, and favoring people who are perhaps at the margin of qualified but could easily improve. The spirit of American affirmative action appears to be the latter, although it's surely implemented with greater and lesser degrees of faithfulness to that ideal.)