Usage and Grammar

Q. I often find myself with questions about verb tense in indirect speech. When the main verb is in the past tense (e.g., said, argued), should subordinate verbs also be shifted into the past? For example, in the sentence “Military supporters claimed that the purpose of a nation’s standing army is to fight wars, not keep the peace,” I am inclined to change is to was. A cursory web search reveals that “backshifting” is a hotly debated question; does Chicago have a position on it?

A. We don’t have a position on it, because writers must be free to use the tense that their meaning requires. You could make a rule that the past must always be used, but that would result in universal ambiguity: “They pointed out that as humans we were fallible” leaves open to question whether we still are. The present tense in “They pointed out that as humans we are fallible” more clearly implies that humans are still fallible today. To restrict writers with an arbitrary rule in this case is not in the interest of clarity.