How is it that this is legal when there isn’t a vacancy yet? Could Trump have appointed a successor to Thomas in 2020 even if he stayed on the court till 2026?
I don't know if there's any past precedent for "confirming" a new justice when the current seat ISN'T vacant yet (although I imagine Justice Breyer DID notify them in writing that he will step down and retire at the end of the court's current session)
I recall that Bush nominated Roberts for Sandra Day O'Connor's seat when O'Connor was still on the court, but whether you could actually "confirm" that appointment was rendered null when Rehnquist died, and Bush withdrew the nomination and (foolishly) selected Roberts to fill the vacancy instead.
Were Souter, Kennedy, and Stevens still technically "serving" on the court when their successors were confirmed? I can't recall if they were or not.
I believe in the case of William O. Douglas and Thurgood Marshall seats being filled, both of them attended the confirmation hearings of their successors and maintained an office at the Supreme Court and clerks AFTER their successor was confirmed, but nevertheless they were still officially "retired" at the time of their successor's confirmation, and had no voting power on the court, merely a "right" to hear cases as non-voting retired judges who were guests of the court.
This looks like some murky legal ground that is best left to a legal body like the Supreme Court to decide, except all nine members would have recuse themselves. ;-)
(On a related note, the GOP Senators SHOULD have tried to drag their feet on this appointment and delay a floor vote from occurring as long as they possibly could. I would have kept trying to send it back to committee for endless "witnesses" and testimony about Judge Jackson's background before I could "decide" on her fitness for the court.)