Subjective and Objective Case

[Derek]

"He is smaller than she" and "He is taller than I" are examples of personal pronouns in the subjective case. OED abridged reads: Traditionally, it has been said that personal pronouns following 'than' and 'as' should be in the subjective rather than the objective case.

My sensibility accords with this, as OED abridged goes on to say that the personal pronoun is standing in for a full clause, e.g., "He is taller than I am tall." Presupposed in this proposition is the proposition that 'than' and 'as' are conjunctions. Another point of view holds that 'than' and 'as' are prepositions. Now, if 'than' and 'as' are prepositions, the objective case is the proper case following 'than' and 'as', e.g., "She is taller than me."

So, will you help me settle this matter: are 'than' and 'as' conjunctions, or are they prepositions? And if they are prepositions, how does this determine the objective case as the proper one?

Derek.