No particular opinion about Sotomayor. She'll most likely replace Souter, Republican whining notwithstanding, and actually that's not very interesting. Souter's a liberal; Sotomayor's a liberal; the balance of the court will be unchanged.
At the risk of being excessively morbid, here's what matters, in roughly increasing order of importance:
- Breyer: 70 years old.
- Stevens: 89 years old (!).
- Ginsburg: 76 years old.
- Kennedy: 72 years old.
- Scalia: 73 years old.
- Life expectancy at birth for American men: 75.15.*
- Time to Election Day 2016: roughly 7 years and 5 months.
It's a cliché by now to remark that the most enduring political successes of Bush 41 and Bush 43 were their Supreme Court nominations. Thomas, Roberts, and Alito are not only uncompromisingly hard-right conservatives; they're all 60 or younger and will probably stay on the court into the 2020s. The ascension of Alito to replace O'Connor was a particular disaster. Gonzales, Meredith, and Ledbetter were only the beginning. We're going to see many more ugly 5-4 decisions in coming years.
But if Obama gets re-elected in 2012, there's a non-negligible chance that he'll get to nominate five or six justices to the court in total, swinging the balance back to a liberal majority — maybe even a 6-3 majority.
Of course, that's assuming a number of coins all come up heads. It's far from certain that Obama's going to be re-elected; it's far from certain that Senate Democrats won't lose the majority or simply cave to Republican demands for conservative nominees; and I wouldn't be surprised if Scalia manages to hang on by his fingernails until he's 110. But the point is that it wouldn't take a miracle for such a dramatic transformation to occur within Obama's Presidency.
Is this surprising? Upon reflection, not especially. On scotusscores.com, the recent 1994-2005 stretch stands out as an unusual period of stasis — as J. Toobin remarks in The Nine, it's the longest interval the court's ever had with the same nine justices. But when justices stay together for a long time, it means that they're also from the same age cohort**, and therefore that they'll also reach retirement age together. O'Connor's retirement and Rehnquist's death were just the leading edge of a generational turnover that will run its course over the next decade or so. And since both parties are now savvy enough to nominate young justices, we can look forward to another relatively long period of stasis after that.
Incidentally, this also means it would be wise for the other liberal justices — Breyer, Stevens, and Ginsburg — to follow Souter's lead and retire as soon as possible, while it's certain who will be nominating and confirming their successors. But reading Toobin's book has convinced me that Supreme Court justices aren't unusually wise, so it's anyone's guess what they'll actually do.
*OK, time for the caveats. Mean life expectancy at birth is a misleading measure for seventysomething Supreme Court justices. Causes of "young death" like infant mortality and teenage driving accidents and AIDS significantly reduce mean life expectancy at birth, but have no relevance to the life expectancy of people who have passed those filters; so the life expectancy of a 73-year old is considerably higher than the life expectancy of a newborn. Furthermore, Supreme Court justices have an excellent government-funded health care plan, and disagreeing with the politics of the President who would nominate your successor to the Highest Court In The Land is a strong motivator to look after your health. And the probability that Scalia would leave the Court not in a coffin while there's a sitting Democratic President is basically nil. All in all, I suspect that at least one of Scalia or Kennedy will stay on the court past his 80th birthday. So 6-3 is a long shot. 5-4 doesn't seem too unlikely though.
**OK, excluding Thomas, who was an outlier on the Rehnquist Court in more ways than one.