There has been some muted comment about the religious composition of the U.S. Supreme Court after a Kagan approval: 6 Catholics, 3 Jews.
Is this enough Jews, though? Let’s crunch numbers.
First permit me to switch from religion to self-identifying ethnicity, which is closer to how this stuff actually works. Less than two percent of non-Hispanic white Americans are religious Jews, but around five percent have Jewish ancestry and consider themselves to some degree Jewish. Let me just take, as round numbers, 220 million non-Hispanic white Americans, ten million of them self-identifying (to some degree) Jewish. You can of course rework the following with different numbers if you like.
There are nine seats on the U.S. Supreme Court. By general agreement (it seems to me) there is one quota-seat for an African American, one for a Hispanic. That leaves seven seats available for non-Hispanic white justices. How many of those seven would we expect to go to Jewish nominees?
Leaving aside the obvious temptation to carry out a 5,000-word analysis on that word “expect,” let’s drastically simplify: let’s pick ’em by IQ. Supposing non-Hispanic white Gentiles to have mean IQ 100 and Jews mean IQ 112 (the figure usually cited, though again you can re-crunch with a different number if you like), with standard deviation 15 in both cases, here’s what I get for various cutoff minimum IQs:
You get three Jewish seats round about cutoff IQ 153, which is pretty darn smart — only 43,000 non-Hispanic white Gentile Americans are that smart. At cutoff 165 you’d expect four Jewish seats; at around 178 you’d expect five.
That’s all highly abstract, of course. It assumes up front that anyone actually wants justices as smart as possible, when what presidents usually want is justices that (a) are on their side, lib-con-wise, and (b) are sufficiently bland & unimaginative never to have said or written anything that will raise an eyebrow from the drones on the confirmation committee.
It also assumes that a 180-IQ nominee would be better at judging cases than a 140-IQ-er. That’s not obvious to me. I favor the “sweet spot” notion of IQ, where cognitive ability+sense/wisdom max out around 125-135, the sense/wisdom component then dropping off steeply in higher IQ numbers. If that’s right, we may have one Jewish justice too many!