Any skeptics about lingering racism and gender biases in our society would do well to pay some attention to the Sotomayor nomination and confirmation process (and lord knows there's little other reason to pay attention). Now, when those terms are mentioned people immediately think "But I don't hate Mexicans!" and "I don't oppose her because she has a vagina!" These statements are probably true. Her political opponents (discounting Tom Tancredo) may not hate Hispanics or women, but they are less than shy about concluding that she is not otherwise qualified for the office.
The argument starts from a basic premise: the President chose Sotomayor from a pool of potential nominees which, in theory and according to the letter of Art. III of the Constitution, includes every American citizen because she is a woman and she is Hispanic. It's the basic Identity Politics argument. This conclusion can stand alone, i.e. supported by the belief that white men are, by definition, the most qualified people and others can only be elevated as a form of tokenism or "affirmative action." It can also be based upon a form of logic, which is an accurate description inasmuch as "shit that is wrong and does not actually make sense" is a kind of logic. And it is. It is bad logic.
While the Constitution leaves the door wide open for Supreme Court nominations, in the context of modern politics I think we can agree that the pool of potential choices is limited to people with law degrees. We might go even further and state that the pool is limited to people with judicial experience. Either way, this creates a pool of applicants in which white men are the most numerous demographic. This leads people who are bad at thinking to conclude that the probability of the most qualified individual in the applicant pool being a white male is higher than any other demographic group. In other words, if most judges are white men then the most qualified judge is most likely a white male. Or, to put it another way, if you have 20 socks in your drawer and 15 are white, a blind grab in the drawer is most likely to produce a white sock.
But at this point the logic is already irrevocably shot to shit. The preponderance of white males in the pool of potential Supreme Court nominees supports only the conclusion that a randomly selected member of the group is likely to be a white guy. Race and gender are two variables in the process and qualifications are the third. So to draw an accurate inference about tokenism or Identity Politics we would need to define the pool of qualified applicants and then observe its racial and gender composition. So let's treat Qualification as a dichotomous variable (i.e., either Yes or No).
What would make a judge unqualified? Blatant disregard for the law or inability to interpret it reasonably, either of which could be revealed by studying the percentage of said judge's decisions which are overturned by a higher court. If an appellate court is overturning half of someone's decisions, said judge probably has no idea what he or she is doing. Or he or she has an ideological ax to grind. Experience would also be a measure of quality (hence Clarence Thomas's 12 months on the bench led many to conclude that he was unqualified). But once we have defined this group of people who meet the minimum threshold to be called "qualified," then what? Any Federal judge or state Supreme Court justice who performs the duties of the job without problems is probably "qualified." Who, then, is "most qualified?"
The answer is that no one is, obviously. The top 30 or 40 candidates for the Supreme Court are, on paper, largely indistinguishable. They've all sat on the bench. They all went to big-name law schools. They could all be thrown on the Supreme Court and perform the required duties adequately. So the President's choice is – sit down for a moment, Mr. Beck – personal. That's why the Constitution stipulates that a person should make it. From a group of equally qualified candidates, the President is tasked to choose the person whose philosophy, temperament, and personality mesh with his. After all, this is the choice of a person who will be a major part of defining a President's legacy.
This process is not the damn BCS or the eHarmony personal compatibility test. The purpose is not to develop a computer program to weight characteristics and rank-order the candidates from most to least qualified. It's a process in which the Senate's role is to ensure that the President's choice reaches the threshold to be called Qualified. Beyond that the process is and, more importantly, is intended to be a subjective and personal one. The Most Qualified Candidate is a straw man and the quest to find him (and it's inevitably Him) is a search for last night's thunderstorm.