Tonight I became aware, via a question on Mi Yodeya, of Yovino v. Rizo, a recent Supreme Court case. A federal court of 11 judges heard a case and ruled 6-5. One of the majority judges wrote the opinion and then died before it could be made official. The rest of the court said the verdict stood, arguing that the judge fully participated in the case like everybody else. The Supreme Court disagreed. From their conclusion:
Because Judge Reinhardt was no longer a judge at the time when the en banc decision in this case was filed, the Ninth Circuit erred in counting him as a member of the majority. That practice effectively allowed a deceased judge to exercise the judicial power of the United States after his death. But federal judges are appointed for life, not for eternity.
"Federal judges are appointed for life, not for eternity." That, my friends, is reasoning worthy of the talmud. :-)
I skimmed through the ruling to see if they were, in fact, arguing purely on this principle. Not quite; they note that a judge can change his mind up to the moment the ruling is formalized. So it's possible that, had he lived, he might have done so, though I don't know how often that happens at all, let alone by someone who wrote the majority opinion. But it's still an edge case that ought be considered.
Tangentially, I wonder why they waited at least 11 days from when the opinion was written to when they made it formal in court. Were they on recess at the time? Does it usually take that long -- maybe this is "just paperwork that can be done any time"? If so, courts with elderly or ill justices might want to adjust their procedures, just in case. (You can't fully prevent the problem, but maybe you can reduce the likelihood.)