A couple of days ago, Catherine passed on my explanation for why “whom” sounds wrong in this sentence:
The F.B.I. also arrested two of Mr. Rahim’s associates, whom prosecutors say were involved in the plot.
In a nutshell, the object of “say” is an entire sentence (“_______ were involved in the plot.”), and the subject of this sentence is “who.” We say “the associates who were involved in the plot”; not “the associates whom were involved in the plot.”
But what if the F.B.I. sentence had read:
The F.B.I. also arrested two of Mr. Rahim’s associates, whom prosecutors persuaded to cooperate in the investigation.
This sentence may sound awkward, but the problem isn’t the choice of “whom” over “who.”
The difference between the two F.B.I. sentences boils down to the difference between verbs like “say,” which takes a sentence as its object, and verbs like “persuade,” which has two objects: a noun phrase and a sentence.
This makes sense if you think about the meaning of “say” vs. the meaning of “persuade.” We say sentence-like things, but we persuade people to enact sentence-like things.
We also shout or whisper or think sentence-like things, while asking, ordering, or convincing people to enact sentence-like things. These people are both the objects of our persuading/convincing/asking/ordering, and the subjects of whatever sentence-like thing we want them to do.
In terms of sentence grammar, it’s the people’s status as objects that wins out. The F.B.I persuaded them to cooperate, not they to cooperate.
Complicating matters, of course, is that much-lamented trend: “who” is displacing “whom.” So it sounds fine to say:
The F.B.I. also arrested two of Mr. Rahim’s associates, who prosecutors persuaded to cooperate in the investigation.
Returning to “persuade them to do X” vs. “persuade they to do X,” why does being an object win out, grammatically, over being a subject? As we’ve noted earlier, grammar sometimes gets arbitrary. Indeed it often gets even more arbitrary than this.
If you look carefully at what I’ve just written, for example, you’ll see a sentence that calls into question my entire explanation. The sentence is “These people are … the subjects of whatever sentence-like things we want them to do.“ The problem, in boldface, is the verb “want.”
To see this more clearly, let’s look at one more “F.B.I. sentence”:
The F.B.I. wants them to cooperate in the investigation.
Isn’t the logical object of “wants” here the associates’ cooperation in the investigation? The F.B.I. doesn’t want them; it wants their cooperation. Yet grammar, beating out logic, insists that they are the object of “want.” We don’t say “The F.B.I. want they to cooperate in the investigation.”
Nor do I write “people are the subjects of whatever sentence-like things we want they to do.” Except when pointing this out as an exception.