I found myself wondering what the world would look like if we did, in fact, manage to achieve grammatically accurate use of “I” vs. “me”, and was also perusing the venerable Geoff Pullum’s “Language Log” (although it’s predictable what the contrarian old Scotsman would have to say on the matter! ;)).
My concession to descriptivism is that it’s too late for some of those forms of usage to change. Granted, I find some of Pullum’s arguments unpersuasive. When he states unequivocally that “the copular verb takes accusative pronoun complements” he’s stating it like a law of nature or a broad consensus, which it plainly is not – he’s simply stating an opinion, allegedly bolstered by the fact that such things are “heard constantly in the conversation of people whose status as speakers of Standard English is clear”. But how many such people, and where is it written that “speakers of Standard English” are immune from the fault of hypercorrection?
But Pullum acknowledged that in the course of his work on the massive Cambridge Grammar of the English Language he changed his mind about many things, and so do we all. I’m particularly inspired by his comment that if someone knocks on your door, and when you ask who’s there they reply “It is I”, you shouldn’t let them in because this is probably someone you don’t want to know!
He probably has a point, and I think what we’re dealing with here is a matter of gradation rather than absolutes. I’m willing to concede that “It’s me” is so entrenched in the language that it’s become de facto standard. I think it’s the same with “He isn’t any better than me” mentioned upthread. I don’t know whether it’s because the errant pronoun is hiding in an adjectival phrase or if it’s something else, but regardless, it’s established. It sounds fine. This notwithstanding the obvious meaning that “He isn’t any better than I [am]”.
That’s it. Cases like that are a lost cause. But IMHO a construct like “between you and I” or my previous example “That doesn’t make sense to Jane and I” are so obviously wrong to so many speakers of standard English (see the NPR survey I linked above) that they should just be regarded as hypercorrection mistakes, even if Pullum thinks it’s perfectly fine.
Incidentally, Pullum, contrarian as always, also tried to make the case that “that” was perfectly permissible for a non-restrictive clause, citing a journalist who had used it that way. The interesting thing is that, just exactly as I said in discussing this issue earlier, he couldn’t figure out for sure what the sentence meant until he actually spoke with the author. (Substitute “which” for “that” to create one sentence, then put “that” back in but remove the comma – you have two different meanings.) He also acknowledges that the usage is as rare as an ivory-billed woodpecker, which is about as close as he will ever come to saying that something is “wrong” or at least “non-standard”. 