On August 22, 2102, Glenn Greenwald posted an article on the Guardian's US website entitled The bizarre, unhealthy, blinding media contempt for Julian Assange. In this article Glenn used the following sentence [emphasis added]:
The person who (along with whomever is the heroic leaker) enabled "more scoops in a year than most journalists could imagine in a lifetime" – and who was quickly branded an enemy by the Pentagon and a terrorist by high U.S. officials – is the most hated figure among establishment journalists, even though they are ostensibly devoted to precisely these values of transparency and exposing serious government wrongdoing.Leaving aside the prolix nature of Glenn's prose, which causes problems for those who have difficulty with texts that are not written in short, declarative sentences and who have even more difficulty holding a thought long enough to process a subordinate clause, I wish only to address the flagrant solecism presented by the emphasized text in the sentence given above. We can see from the rule given in the first paragraph that the case of a relative pronoun is determined by its use in its own clause. For most relative pronouns this causes no problem because only one relative pronoun (who) has a marked form for the object case (whom).
Now, along with is an idiom that functions as a preposition meaning ‘in association with’ or ‘in conjunction with’. It is more or less synonymous with together with, which is similarly composed of an adverb plus a preposition and is also an idiom that functions as a preposition.
Clearly then, along with governs the object case and we would expect what follows to be in the object case. However, in this instance, the object is not the indefinite relative pronoun whomever, but the entire clause who
mever is the heroic leaker. Since the relative pronoun takes its case from its use in its own clause, it is clearly the subject of the verb is and so should be in the subject case, not the object case.
The correct usage then is along with whoever is the heroic leaker.
Pronouns often cause even experienced writers and speakers problems because they represent the last vestiges of English's once extensive case system. The choice between I/me, we/us, he/him, she/her, they/them, and who/whom presents the writer with an unexpected choice between the subject case and the object case – unexpected because nowhere else is this choice necessary and the writer is not used to exercising it. Still, a word to the wise is sufficient and doubtless Glenn will be on his guard against repeating this error.