Well, that headline may represent a slight exaggeration of the truth, but we live in momentous times, people, because the writing could be on the wall for one particular misplaced comma.

You may remember that in A Comma You Should Cull, the last instalment of my self-editing series, I recommended that writers take out commas before final conjunctions in compound predicates. I pointed out that by doing so, authors give passages in which those commas are culled just a little more forward momentum than they otherwise have. I also mentioned that The Chicago Manual of Style’s rule 6.29 recommends you shouldn’t use such commas, but I said the rule is ‘badly written and confusing’, which might explain why it often isn’t applied correctly. (I found that very difficult to write, by the way. I love The Chicago Manual of Style. If the University of Chicago Press built a shrine to the manual, I would happily travel all the way to the States from my Mediterranean island just to chant, burn incense and strum a guitar in front of said shrine – and I can’t even play the guitar.)

Writing that post helped me collect my thoughts on the topic, and last Sunday I decided I might as well sit down and write an email to CMOS sharing my thinking with them, too.

CMOS replied yesterday. And they said they agreed with me.

They didn’t quite come out and say that the next edition of the manual is going to be called Marcus Trower’s Chicago Manual of Style, but they sort of implied it by telling me they’re going to put my note in the file for the next edition. So that’s the message I’m taking home, anyway. Here’s our correspondence:

My Message
The Chicago Manual of Style is a truly wonderful resource. I’m a copy editor and a Brit, and no style manual in the UK comes anywhere near to matching CMOS in terms of range and detail. With CMOS by my side, or a few clicks away online, I feel like I have an authoritative companion as I travel the highways and byways of written English. But there’s a but coming. Very occasionally I detect what I perceive to be a glitch in the manual, and I’d like to talk a little about 6.29, the rule for commas with compound predicates, because I believe that, with a little adjustment, 6.29 would get across what I’m fairly sure is its intended meaning, something the rule isn’t quite doing at the moment. Here is the first sentence of the two-sentence rule:

A comma is not normally used between the parts of a compound predicate—that is, two or more verbs having the same subject, as distinct from two independent clauses (see 6.28).

The problem here is that though the rule acknowledges that a compound predicate can consist of more than two verbs, it’s formulated for a two-verb compound predicate only. Here’s a three-verb compound predicate:

John got up, went to the kitchen and made coffee.

This compound predicate has three parts, and a comma separates the first part, “John got up,” from the second part, “went to the kitchen.” If the sentence had four parts, there would be two commas, etc., etc. So, the way the rule is currently phrased is not quite correct, since commas are normally used between parts of a compound predicate, just not the final two parts. A better way to phrase the rule might be:

A comma should not be used between the final two parts of a compound predicate, unless using a comma would prevent a misreading.

In the case of a two-verb compound predicate, the first and second parts are also the last two parts; therefore, no comma is used.

Might I suggest you also give a three-verb compound predicate as an example in 6.29, alongside the two two-verbers you currently have. I know from experience that 6.29 can create a little confusion among editors and writers, and I think that providing a three-verb sentence to illustrate the rule would help immensely. Writers and editors often mistake a sentence with a three-verb compound predicate or more for a list and place a comma before and, when and is the final conjunction, because they believe they are adding a serial comma. If you gave a three-verb example sentence with a compound predicate without a comma separating the last two parts, that would help clarify the difference between a list and a compound predicate.

The Reply from CMOS
Thank you very much for taking the time to explain this issue. I agree with you! I’ll be happy to put your note in the file for the next edition.