English is complicated and can confuse the best of us. Many editors have dog-eared grammar manuals and style books with Post-It notes on the sections we have to double-check every time. One fine point that even experienced editors find hard to memorize is the distinction between who and whom.
The short answer to the who or whom question is that who is for subjects and whom is for objects. Only it isn’t that simple, or why would we all keep asking one another, “Is this right?”
As you’ve probably realized, the problem is declension.
Who, what, and which are all interrogative pronouns as well as relative pronouns. That is also a relative pronoun. Who declines, while the others don’t.
For guidance, look to personal pronouns, which also decline.
Clears everything right up, doesn’t it?
One way to remember which pronoun to use is to rewrite the sentence with they or them instead. Them and whom both end with m, so where you would use them, use whom.
Linguists have debated for decades whether whom is so unmanageable it ought to be retired, and who treated like all the other relative pronouns. Advocates of common usage say who can—and often is—used without confusion in places where whom was traditionally used. For example: “Who did you meet?” Advocates of traditional usage argue for maintaining the distinction because…well, because it’s traditional. If this is the camp you choose, here’s how it’s done.
Interrogative nominative: Or, as we say in English, a question’s subject.
Who came to dinner?
It was who?
Interrogative objective: Which is to say, a question’s object. In these examples, he is the subject. Whom is the object of a verb or preposition.
Whom did he invite to dinner?
To whom is he referring?
Watch out for those nested clauses
Bryan Garner points out, in his chapter on grammar in The Chicago Manual of Style, that the inverted syntax of some questions misleads people to use whom when who is called for, as in the incorrect “Whom should I say is calling?” It might seem that since the word I is the subject, whom must be the object. But there are two clauses here. “Should I say” is inserted into the clause “who is calling.” Who is the subject of the verb calling.
Nested clauses can also cause confusion when using relative pronouns. Use the nominative case if no subject comes between the pronoun and the verb. But if a subject intervenes, the pronoun must match the clause that contains it.
The intern who joined us today is smart.
The intern, whom I thought punctual, missed her deadline.
I did the thinking, so whom is in the objective case in the nested clause, even though the intern is the subject of the surrounding clause, “The intern missed her deadline.” Sometimes you must take your sentence apart to ensure you get the right pronoun in each clause.
Choose your style
Because its traditional use has diminished in everyday speech, whom is seen as formal and old-fashioned—in a good way. If you want to be seen as a traditional, formal writer—or are writing about a traditional, formal character—then continue observing the finer points of whom usage.
But, as The Yahoo Style Guide says, “If all else fails, use who.” Yes, Yahoo, as you might expect, falls on the casual side. That’s because sometimes the traditionally correct form (e.g., “Whom did he invite to dinner?”) sounds not just old-fashioned, but also stilted.
In fiction, whether you choose the traditional or casual form will depend on the character. A college freshman is likely to use who in all cases, whereas the college president will be meticulous in his use of whom. Consider then the ramifications of the freshman who is meticulous about whom, or the one who tries using whom to sound smart but winds up using it wrongly.
In nonfiction, your usage depends on your audience. You may side with Yahoo and the linguists, choosing common usage and writing who in all cases except those with a preposition (e.g., “To whom did he send invitations?”). Know your audience well enough to determine whether they will find “Who did he invite?” casual—in a good way.
Download the PDF version of this article: When to use who and whom