Early in "The Pelican Brief" by John Grisham, two Supreme Court justices met their deaths. The GOP leader of the Senate has been quoted as saying that if the GOP regains control of the Senate in 2022, he will refuse to even hold hearings - meaning no confirmation on any nominee from a Democratic president. I'm guessing that will now be SOP for both parties - no confirmation if the Senate is in different hands that the presidency.
That brings up the question - suppose there were multiple vacancies on the Supreme Court, say 3 or 4 vacancies, how would the smaller-member court operate? Would a 3-2 majority decide a case? Would it set a precedent? Would they still require 4 votes to consider a case?