This being a blog, though, what I'm going to focus on is the silliest of the proposed questions, from Ann Althouse, a professor of law at the University of Wisconsin:
If a diverse array of justices is desirable, should we not be concerned that if you are confirmed, six out of the nine justices will be Roman Catholics, or is it somehow wrong to start paying attention to the extreme overrepresentation of Catholicism on the court at the moment when we have our first Hispanic nominee?
I'm guessing that this question is a joke, but just in case it's serious . . . My impression is that, for about 150 years, an overwhelming majority of Supreme Court justices have been Protestant. I can't imagine that, when, say, Charles Evans Hughes was being nominated for his Supreme Court seat, that somebody asked him: "Is it somehow wrong to start paying attention to the extreme overrepresentation of Protestantism on the court at the moment when we have our umpteenth white nominee?"
To do a quick check on the numbers, I did a quick Google search and found this page with the religious affiliation of all 109 Supreme Court justices up to this point.
We've had 12 Catholics, 7 Jews, 1 unaffiliated, and 89 Protestants (in decreasing order of frequency, Episcopalians, Presbyterian, Unitarians, Methodists, Baptists, a few others with one or two each, and a bunch of Protestants not further defined):
(As noted on the linked webpage, there's some ambiguity as to whether Episcopalians should be characterized as Protestant, but for the purpose of ethnicity, I think the label fits here.)
Most of the Catholics and almost all the Jews on the court were appointed since 1930. All the data are on the linked webpage, so feel free to make your own fun graphs.
P.S. In response to some of the early comments:
1. By making this graph, I'm not "defending reverse discrimination." I'm just pointing out that we've had about 200 years during which white Supreme Court nominees could've been asked, "Is it somehow wrong to start paying attention to the extreme overrepresentation of Protestantism on the court at the moment when we have our umpteenth white nominee?" It just seems a little silly to start asking this sort of question right now.
To put it another way, I agree that intellectual diversity of opinions is a good thing, but I think Althouse's "Is it somehow wrong" formulation is just silly. If you want to ask about diversity of opinions, you can do it directly without talking about "extreme overrepresentation" in a historically context-free way.
2. One commenter asked about other religions. They are shown on the chart above.
P.P.S. To get to a more interesting statistical question hinted at by Althouse, it is indeed impossible for any collection of 9 people to be truly diverse. Beyond the ethnic and religious dimensions already mentioned, there's the division between politicians and non-politicians, lawyers and non-lawyers, lawyers with and without business experience, and so on. As noted above, I think it's a bit odd to suddenly be bringing up overrepresentation of Catholics now, given the historical record, but some of these other questions of breadth could be relevant.
P.P.P.S. Commenter John S. at my other blog linked to this excellent news article by Robin Toner from a time two years ago when questions arose about there being five Catholics on the Supreme Court. Oddly enough, nobody was asking, "is it somehow wrong to start paying attention to the extreme overrepresentation of Catholicism on the court at the moment when we have our umpteenth white nominee?"