During the Democratic debate on March 15, Senator Bernie Sanders said, “One difference between Joe and I is . . .” Nearly three decades before, then-candidate Bill Clinton said, “Please vote for Al Gore and I.” It’s also a favorite bungle of Senators Chuck Schumer (D., N.Y.) and Cindy Hyde-Smith (R., Miss.). The misuse of a nominative for an objective pronoun is nothing new, and it knows no party lines: Republicans and Democrats alike make the mistake.

Americans in general seem prone to it today. A generation ago, it was one clear mark of the uneducated speaker, only a notch above It don’t make no difference.

The problem that pronouns raise for speakers of English is that we don’t normally inflect noun elements to reflect their function in a sentence. That is, table remains table when subject or object. (That’s not true in Latin, for example: The word changes its ending according to its function — mensa as subject and mensam as object.) With pronouns, however, it’s different: We have six sets of English pronouns that change form — I/me, we/us, he/him, she/her, they/them, and who/whom. Those are the only six.

Each of those six pronouns has two cases. The pronouns in the nominative (or subject) case are I, we, he, she, they, and who. The pronouns in the objective (or object) case are me, us, him, her, them, and whom. The objective case is called for whenever the pronoun is the object of a verb (She called me) or the object of a preposition (She sat beside me). Only linking verbs (such as be-verbs) take a nominative in the predicate (It was I who called her).

The trouble Bernie and Bill had arises typically when a pronoun is coupled with another word (She called Jim and me) (She sat beside Jill and me). There’s a weird tendency to want to use I in those instances. Teachers have traditionally admonished their students to leave Jim and Jill out of the equation: Omit the first element, and what would you say? You’d never say *She called I or *She sat beside I. (In linguistics, the asterisk indicates a nonstandard construction.) So the pronoun shouldn’t change with the addition of another noun element, when both are objects of the verb.

In the second paragraph of this piece, I called the nominative pronoun in this kind of construction a “mistake.” But is it really? Is it still considered an outright error to say *The difference between Joe and I is . . . ? Does it deserve an asterisk? It might surprise you that modern linguists and grammarians are divided on the point. The British are leading the charge on calling it Standard English. Two British grammarians, Rodney Huddleston and Geoffrey Pullum, have said that the usage is “so common in speech and used by so broad a range of speakers that it has to be recognized as a variety of Standard English” (The Cambridge Grammar of the English Language, 2002). A popular writer on language, the Times columnist Oliver Kamm, has blogged that “a pronoun within a coordinate phrase is free to take either nominative or accusative case.” Presumably he’d be happy with *Please call her and I.

My own empirical findings are to the contrary. Big data allows us to assess the relative frequency of alternative constructions in a way that is most useful to grammarians and lexicographers. In 1820, the phrase between him and me outnumbered *between him and I by a ratio of 93 to 1 in print sources. Today the ratio is 53 to 1. Granted, that’s big data, so included in the mix are all the instances in which novelists have tried to signal through dialogue that a speaker is ill educated or socially insecure.

But if you take the phrase between you and me versus *between you and I, the ratio today is only 16 to 1. Much closer. Even so, the disparity in frequency is quite pronounced — and it’s not nearly close enough to call *between you and I an example of Standard Written English.

But what about spoken English? Lawrence Summers, the president of Harvard University, used the phrase in an interview a few years ago. Is that enough to make it standard? I think not. But this gets into thorny questions of right and wrong, and the simple dichotomy disserves linguistic commentators.

That’s why, in 2009, I created the Language-Change Index to gauge the relative correctness or incorrectness of questionable usage. Stage 1 is clearly wrong; Stage 5 is clearly right. Here are the gradations: Stage 1 (rejected in Standard English); Stage 2 (spreading but widely shunned by educated speakers); Stage 3 (widespread but rejected by most copy editors); Stage 4 (ubiquitous but rejected by many punctilious copy editors); Stage 5 (fully accepted and objected to only by eccentric reactionaries). It’s rather like linguistic epidemiology. By Stage 2 we’re seeing community spread.

In my Oxford University Press book Garner’s Modern English Usage (2016), I’ve declared *between you and I to be at Stage 2. Now, four years later, I might reluctantly put it at Stage 3, given the frequency of its appearance in the speech of educated speakers. Experience tells us that once it gets to Stage 4, then the next stage — full acceptance — is inevitable with time. And as we’ve seen, some Britons already want to peg *between you and I at Stage 5.

Earlier I mentioned the “socially insecure.” Why? Because the misuse of I for me has for many decades been considered a hallmark of hypercorrection. That’s what linguists call it when an ill-schooled person makes an error by attempting to use a prestigious form of language — but gets it wrong. That is, people mistakenly think that me or us is somehow rural or uneducated. That’s because they’ve been corrected for saying Me and my friends went to the playground and admonished instead to say My friends and I went . . . Overgeneralizing, they came to think that there’s something wrong with the word me.

None of these problems have been helped by the tendency, throughout the English-speaking world, to drop grammar from school curricula — the subject of our next column.

Editor’s Note: In this issue, we introduce a regular column on English grammar and usage by Bryan Garner.