The standard wisdom about case of pronouns that are predicative complements (and that includes many complements of "than" and "as") is that if you could fill in a clause instead of a pronoun, and in ...

Many years ago, back when I used to answer my landline telephone, I found myself in a conundrum. I realized that, when a caller asked, “May I speak to June, please?” I would answer, “This is she.” But ...