Stephen Breyer’s decision to stay on the SCOTUS for at least one more term is likely to play out as follows:
(1) Assuming Democrats retain control of the Senate until then (I would say the odds of this are 80% at best, so we’re looking at a massive downside risk), and that Breyer doesn’t suffer some sort of disabling health crisis (he turns 83 next month; the odds of the average 83-year-old dying over the next 12 months are 5.98%, although Breyer’s odds are no doubt better if only because of class factors), I think it’s quite unlikely that Breyer announces his retirement at this time next year.
Why? Because Breyer has argued himself into a corner, in which the more obvious it would be that he would be engaging in strategic retirement, the more unacceptable doing so will be to him. Retiring immediately before the 2022 election would be the most obvious possible strategic retirement. Therefore, per his own many public assertions that retiring in this way would hurt the non-partisan credentials of the SCOTUS, he just won’t do it, on “principle.” (By a striking coincidence, maintaining this principled stand in the face of public criticism also allows him to do what he wants to do anyway, which is not to quit.)
(2) What if the Democrats lose the Senate next November? Does Breyer resign immediately, subject to the confirmation of his successor? The new Senate doesn’t take office until the first week of the following January, so there would be a two-month window to replace him.
The answer to this question is, it doesn’t even matter whether he does or not, because I can pretty much guarantee that in this scenario Biden couldn’t get the reanimated corpse of Antonin Scalia confirmed. All 50 GOP senators will be in rock solid total opposition to confirming a replacement in such a scenario, and there’s no way at least one Democrat doesn’t defect. In fact I would expect several to do so — collegiality and precedent and 10,000 columns from centrist noobs about how two wrongs (the first wrong being McConnell’s blocking of the Garland nomination) don’t make a right make that basically inevitable.
(3) If the Democrats hold the Senate, then I do think Breyer is likely to resign at the end of the 2022-23 term. The outcry at that point would be so intense that I think he would finally fold.
(4) If Democrats lose the Senate, there is zero chance that the GOP will allow Biden to fill the seat, ever. And by that I mean that they won’t fill it for six years, if Biden should get re-elected and the Dems don’t get the Senate back in 2024 or 2026. Anybody who thinks otherwise hasn’t been paying attention.
Whether such a development would heighten the contradictions enough to allow for substantial reform the next time the Democrats hold the trifecta . . . well, if wishes were horses beggars would ride.