The pushback on Judge Sonia Sotomayor is about what you'd expect from a party that hasn't quite figured out why women and people of color don't tend to vote for them in large numbers--that Judge Sotomayor is an affirmative action pick (Pat Buchanan), that she's a racist (Tom Tancredo), that she's an unabashed liberal (Karl Rove), and so on.
The easy answer is that Judge Sotomayor is not qualified in the eyes of these people simply because President Obama chose her, and that Jesus Christ wouldn't be acceptable if he'd been offered the job by a Democrat, and that any consideration given to a nominee's gender, race, ethnic background, sexual orientation (i.e. anyone other than a straight, white male) is necessarily a limiting factor in just how seriously we can take this person as a candidate. Because straight white males never have a hand up in this world, they hint, straight white males are by default always in the running for the title of "Most Qualified Candidate."
Consider for a moment how silly the suggestion that a "Most Qualified Candidate" for anything actually is. Even in those areas as quantifiable as athletic competition, it's nearly impossible to come up with a consensus as to who is the very best at any given moment. Tiger Woods is the exception that proves the rule, and even he hasn't been the best golfer in the world since his return from knee surgery. So why should we assume that there's a "Most Qualified Candidate" when it comes to a Supreme Court nomination?
A few weeks ago, when Justice Souter announced his retirement, Mark Halperin (or his headline writer, one) suggested "white men need not apply" for the job, and the howls of the defenders of privileged white men everywhere were loud and long. "Find the best candidate first," they screamed. "You shouldn't choose a nominee just because of skin color or gender," they yowled, as though restoring a woman to the Court (to bring it all the way up to 2) would be the height of injustice.
These people act as though there's a single superstar judge toiling away in the minor leagues of Federal Appellate Court just waiting for someone in the bigs to blow out a knee so he can be called up and have his chance to shine in the Big Show. The reality is that there's an enormous pool of people who qualify for the job, and a President's job is to find one of them he (and in the future, she) feels will do the job.
One reason that the defenders of the straight, white male judge flame are howling so loudly over this is that this move on the Court is just the latest sign that their (our, since I'm one too) era of unquestioned dominance is over, and our unassailable privilege is leaking away too, and quickly. They don't like that because it makes them actually wonder if their accomplishments came as a result of merit or as a result of an old boy's network that rewarded straight, white masculinity in the way they imagine Affirmative Action rewards skin color or Title IX rewards being a woman or ENDA would reward being gay (if it ever passes). They can't deal with that challenge to their egos, so they lash out and prove themselves to be just what we thought they were--out of touch and frightened of the future, hanging onto a mythical view of the world and thinking that if they just say what they believe long enough and loudly enough, it'll be true.