" Ostensibly that would be Breyer's seat as he is the oldest, but it could be (please let it be so) Ginsberg's seat. "
I think John Paul Stevens (born in 1920) is the oldest. Ginsburg (born in 1933) is getting up there too. Time for both to retire.
I knew I would probably screw up the names of the Justices and their relative ages. But on one thing we can all agree, Breyer, Stevens, and Ginsberg all need to retire yesterday.