Manuscript Preparation, Copyediting, and Proofreading

Q. I’m editing a book on King Lear that is supposed to follow U.S. style. The author seems to favor the spelling “theatre” throughout, in both senses of the word: the physical setting of performances, as well as in the generic sense of drama. M-W lists this spelling second, the first entry being “theater.” Should I change “theatre” to “theater,” or let it stand, as it is an equal variant?

A. It can be counterproductive to override an author’s choice between equal variants, because if the author is consistent, the editor risks introducing inconsistency by meddling. If the author is inconsistent, feel free to impose your preferences.