, and bishops must be unmarried.
That’s more “shall” than “must”.
Both east and west switched to unmarried (or widowed) bishops in the second century, partly from the tendency to choose monastics, but more importantly over inheritance issues. It’s an issue of discipline, rather than dogma.
That said, it has been many centuries since anyone not already a bishop was elected bishop of Rome. While it used to be
quite common to elect a deacon, particularly the head deacon of Rome, it has, again, been a
very long time . . .
So the answer is, “yes, he
could be elected, but neither he nor any other non-bishop has any realistic probability of being elected.”
(then again, there’s the hysterical movie, “The Pope Must Die(T)”, in which a mob scheme to select a compliant cardinal goes bad due to a a nearly deaf secretary cardinal, placing a bumbling fat rural priest on the throne . . .)
hawk