Let this William Warren cartoon represent what I'm calling a meme because I'm seeing it everywhere:
When a white man gets onto the Supreme Court, it's because of his legal credentials, because he got no points for diversity, but when a woman or a member of a minority group makes it onto the Court, she (or he) will be forever marginalized as an embodiment of the quality or qualities that clinched the appointment, even though excellent legal credentials were required for her to make it into the pool of finalists. Don't you see how unfair this marginalization is?
The fact that Sonia Sotomayor is female and Hispanic and that she got the nomination because of that does not nullify or degrade the legal credentials that she also has. It is wrong and unfair to say that it does.
Now, it's a separate question whether being female and Hispanic is supposed to play a part in constitutional interpretation. Both Obama and Sotomayor have made statements that suggest they believe something that many lawprofs say all the time: That a judge's background experiences and understandings play a role in answering hard questions of interpretation.
If you don't think that is true, think deeply about why you disagree. What do you know about the how human mind works that makes you think that our reasoning is abstracted from our real-world context? Don't tell me that you just feel sure that's what judges ought to do. The question is what human beings do, not what you wish they could do and would do.
And frankly, I think that if judges could reason about legal texts abstracted from the real world, they would make all sorts of intolerable, ridiculous decisions that would lead us soon enough to replace them with more practical judges. If your wish came true, it would only be temporary.
It's also a separate question whether Presidents should make Supreme Court appointments based purely on legal credentials. Is there some idea that all possible nominees could be ranked and the President ought to choose #1? Assuming some absolute rank order is possible — and I don't think it is — would you want to limit him that way? Why? What if it meant that the next 100 judges would be white males from upper middle class backgrounds? I think that would be intolerable.