Of all the justifications for racial preferences, "diversity" is the most beloved by preferences' defenders, because it's so wonderfully straightforward, in a question-begging way: how can the goal of "diversity" be achieved, after all, except by altering standards to ensure the right level of diversity? Mark Kleiman, in a lengthy meditation on Glenn Loury's statistical argument to that effect, comes down in favor of "arguing frankly about the terms of the tradeoff" between diversity and color-blindness. He's clearly unhappy with the current de facto quota system in university admissions, but having accepted the legitimacy of the diversity goal, he's pretty much lost the argument before he's even started.
The cleverness of the "diversity" argument is that it, like so many other arguments about race in America, hides its true meaning behind euphemism and deceptive ambiguity. In the short term, "diversity" is simply a euphemism for ensuring that a given population (say, a university student body) contains the requisite number of members of certain minority groups--i.e., quota-setting. As such, it should be easy to argue against, in the same way that the euphemism "affirmative action" hardly stops its opponents from arguing against quotas. However, diversity has a longer-term meaning that is much harder to argue against: to "value diversity" is, implicitly, to accept laudable principles like racial equality, non-discrimination against minority groups, and racial integration at all levels of society. After all, if it doesn't bother you (as it evidently does Kleiman) to see, say, a classroom with virtually no black students in it, then how can you really support these values?
And here's where the short- and long-term meanings of "diversity" can actually diverge, in an interesting--and, I believe, very telling--way. Now, I happen to be an enthusiastic supporter of all the ideals encoded into the long-term meaning of "diversity", but I vehemently oppose it in its short-term sense. My justification is simple: I have literally not the slightest doubt that color-blind policies will lead, in the long-term--and probably sooner than most people expect--to "diversity" in the short-term sense (i.e., representation levels of minority groups in, say, university populations--including elite ones--that are approximately proportional to those groups' presence in society at large). After all, eventual integration into, and mirroring of, the overall traits of the general population has been the fate of every single other racial or ethnic minority in the history of America. And while each group's history has been different (with that of African-Americans being a particularly striking anomaly), no group today can claim any conditions (and especially not levels of racism) which were not also experienced by past groups that nevertheless eventually assimilated completely. There is thus no reason to think that the future of any current minority group will be any less bright.
But if I believed differently--if I imagined that the current disparities in, say, qualification for elite colleges among racial and ethnic groups--were set in stone (or at least likely to persevere into the indefinite future), then I might conceivably feel quite differently, as well, about colorblind policies which by implication perpetuate these disparities. And it does seem as though supporters of "diversity"-based racial preferences adopt a "what else can we do" attitude that suggests a belief that these disparities will not disappear on their own. And so I ask supporters of these policies: do you, indeed, doubt what I take as self-evident--that reversion to the mean is simply a matter of time? And if so, then why do you believe that today's minority groups will fail where so many others have succeeded?