WRONG: Who should the United States befriend?

RIGHT: Whom should the United States befriend?

Harbrace Handbook of English p.78 (1951)

The conversation turned 'round to a grammar question the other evening. Who vs. Whom? Miss M was studying and we did not have the benefit of her input. We tossed around a few "virtually essential" possible rules based on For Whom the Bell Tolls and finally decided that it was an empirical question, the answer to which would likely be found in a crappy old book.

To that end, and since nothing of import happened in the World, on the World Wide Web, or on the Farm today, I present to you Who, Whom, and Whose.

"Wait just a gall-dang minute," you're shouting. 

Alright, already! I hear ya! There's no need to shout. You'll wake the dogs.

"Why get Whose-- or for that matter Who's on First-- involved in this? I thought you were just going to 'splain when to use Who and when to use Whom! Not that I care all that much anyway, Marica. I mean, really, Who cares?"

That's a fine point, but hear me out. Leaving Whose out of the picture would be like saying "I-me-" and forgetting "mine." And that just don't seem right. If you're going to say, "I" and "me" why not just finish what you intended to say and say "mine?"

Who, and it's forms, Whom and Whose, are pronouns. Unlike most nouns (en inglés, que es) most pronouns change case based on how they are used in the sentence. The interrogative and relative pronoun Who is no different than most. Used as the subject of a sentence or clause, one uses the nominative case Who. As the object of a sentence, clause or preposition, the objective case Whom. And as a possessive relative pronoun, the possessive Whose.

I found this helpful:

A Writer's Manual and Workbook Enlarged Edition p.46 (1944); See there? I-me-mine. Note: singular and plural relative pronouns have the same form. Thank the Lord!

Let's re-write the WRONG and RIGHT question sentences which use the interrogative Who as

The United States should befriend ___Who / Whom___?

Let's re-write the re-written WRONG and RIGHT question sentence as if it were answered.

The United States should befriend ________. 

[Pick a country. Any civilized country will do-- it's grammar, not foreign policy.]

Clearly, your civilized country of choice is the object of the sentence. Thus, in the question we need the objective form Whom.

The WRONG / RIGHT example comes from The Harbrace Handbook of English, Whose author notes

Before the verb, the interrogative who is acceptable colloquial English, but formal English requires the objective whom.

With respect to Who as a relative pronoun, I initially found this, from The Writing of English (1938), virtually essentially useless:

The case of a pronoun depends entirely upon its syntax; it may or may not be in the same construction as its antecedent:

I saw a man who knows you.
I saw a man whom you know.

I thought just as virtually essentially useless-- especially if you are a smidgen rusty on the vocabulary of grammar, as am I-- was this from The Essentials of English Composition Revised Edition 1945):

A pronoun that joins a dependent clause to a substantive is called a relative pronoun. Careful writers use who to refer to persons, which to refer to things, and that to refer to persons of things.

1. That is preferred to who or which (a) when the relative clause is restrictive ... or (b) ...

[Keep in mind that That / Which is an interesting issue for which / that I have no time (for) here.]

This, however, was useful (The Essentials, p57):

The case of a relative pronoun, like that of a personal pronoun, is determined by the function of the connective in its own clause, not by the case of the antecedent.

That's the syntax of "depends entirely upon its syntax."

So if a pronoun can join, a noun can separate.

I saw a man. A man knows you. 

Nominative case.

I saw a man. You know a man. 

Objective. 

What could be more simple? 

Subject-Nominative-Who

Object-Objective-Whom

Possessive-Possessive-Whose

RIGHT: Whom should the United States befriend? 

Good question. First answer? The United States.
~~

This post is dedicated to Daughter C, Mike, and A. Leland, without whom I would not have asked the Who / Whom question. 

This post is brought to you by the following crappy old books, without which I could not have answered the Who / Whom question.

A. Howry Espenshade, THeodore J. Gates, and Richard D. Mallery. The Essentials of English Composition Revised Edition. D.C. Heath and Company, Boston. 1945.

John C. Hodges. Harbrace Handbook of English. Harcourt, Brace and Company, New York, Chicago. 1951.

Paul P. Kies. A Writer's Manual and Workbook Enlarged Edition. F.S. Crofts & Co., New York. 1944.

John Matthews Manly, Edith Rickert and Martin Freeman. The Writing of English (Complete Edition). Henry Holt and Company, New York. 1938.