Quoting Ian Zimmerman (itz@???):

> But if "and" is a conjunction in this sentence pattern, the nouns or
> pronouns it joins together form the subject, and so they ought to be in
> the nominative, i.e. "John and I".

Indeed.

I vaguely recall Hendrik suggesting that 'and' functioning as a
proposition makes 'John and me' a suitable subject for the sentence,
i.e., in the nominative case, which I thought a startling notion both
for the idea of 'and' being anything but a conjunction and for the
conclusion drawn. I'd have to check the archive to see if I read that
entirely right -- but definitely the claim of 'and' being a preposition
was part of it.

Not that this is worth dwelling on, unless good for points of benevolent
entertainment.