Bill O’Reilly answered 10 questions in the Sept. 22 issue of Time magazine. In doing so, the Fox News host committed a common grammatical mistake twice. That thorny little issue of who vs. whom.

First O’Reilly said, “I don’t work for a network. So if there’s a person over there who I respect, and they wanted me to do a certain thing, I would consider it.”

Later he said, “I don’t endorse candidates, and I don’t tell people who to vote for…”

In both cases, O’Reilly should have said whom, not who. Use who when describing a subject, the actor of a sentence: I, you, he, she, we, they, who, whoever. Use whom when describing an object, the person acted upon: me, you, him, her, us, them.

Let’s practice.

Obama is the candidate whom the Democrats have nominated. They nominated him; he received their action.

Who will win Nov. 4? Here, who is operating as a subject, synonymous with “he.”

Yes, that’s a handy test: Can you replace it with he or him? He equals who. Him equals whom. But if you want to know the reason behind the trick, it’s simple. Is the pronoun operating as a subject (who) or an object (whom), someone taking action (who) or someone receiving an action (whom)?

Whomever I see first receives an autographed O’Reilly picture. Whoever tells O’Reilly to read Grammar Guard wins a thousand dollars.