The traditional rule also holds that
neither is grammatically singular. In other words, "neither" agrees in number with "is", never "are". I will explain this further below.
[1a]
Neither (candidate)
is having an easy time with the press.
"Neither" modifies the noun "candidate". Both are singular, so the verb is also singular. Omit the noun "candidate" and "Neither" becomes the subject, a noun, a substantive noun, substituting for a noun. It's singular, so the verb is also singular:
[1b]
Neither is having an easy time with the press.
Below, "Neither" takes a prepositional phrase as modification. We know it's modification and not the subject because we can omit it (...) without changing the sentence's core meaning.
[2a]
Neither (of the candidates)
is having an easy time with the press.
The subject is "Neither", its modification is "of the candidates". Omit the word "Neither" and the sentence is rendered ungrammatical (*):
[2b] *Of the candidates are having an easy time with the press.
Omit "Neither of" and the sentence's core meaning changes:
[2c] The candidates are having an easy time with the press. (affirmative)
[2a] Neither of them are having an easy time with the press. (negative)
In short, "Neither" is grammatically singular. Any modification (e.g., "of . . . ") is added info and not privy to subject-verb agreement.
Here's the Non-standard usage: Some speakers,
both learned and lay, switch the order, treating "neither of" as modification:
EX: Neither of
the candidates are having an easy time with the press.
The assumption, the verb agrees in number with the closest noun, and since "Neither" doesn't appear to be a "noun", it's passed over and treated as a modifier. The result, the verb agrees in number with the preposition's object, "the candidates":
EX: Neither of
the candidates are . . .
Though, traditionally, both prescriptive and descriptive takes on the matter, a verb cannot agree in number with a noun that sits inside of a prepositional phrase.
EX:
Neither [of the candidates
] is
The preposition "of" governs its phrase ([...]); nothing can work its way in, not even subject-verb agreement. But . . . speakers have found a way around it. They've split the prepositional phrase, like this,
Standard
Neither [of the candidates] is
Non-Standard
Neither of [the candidates] are
Does that help?
