Jonathon Owen has laced into the Chicago Manual of Style at his blog Arrant Pedantry over the fading nauseous/nauseated distinction. His post prompts me to think about how we go about makling usage distinctions.
But first let's dispose of nauseous/nauseated. Like a good little copy editor, I started out insisting that nauseous must mean "causing nausea," not "experiencing nausea," Woody Allen's dialogue notwithstanding.
But I have long since given up on it, for the reasons that Jonathon Owen states: "If 99 percent of the population uses nauseous in the sense of having nausea, then who’s to say that they’re wrong? Who has the authority to declare this sense 'poor usage'?" Even the Associated Press Stylebook (!) has given up on nauseous/nauseated. Garner's Modern American Usage has not entirely, saying that the "experiencing nausea" sense is so common that it cannot be called an error, though careful writers will avoid it.
I want to turn to the question of who has authority, who gets to sit in judgment.
The answer: You do. You're the editor. It is your job to make decisions about accuracy and precision in usage. If you want to avoid arbitrary and bone-headed decisions, then you will want to go through a series of steps before arriving at judgment.
Item: What do your own ear and tastes tell you? From your education and your range of reading, you have developed a sense of what the best writing is. Of course, you do have to consider that some of what you have been taught is codswallop, so you have to question yourself, which means consulting other sources.
Item: What's in the dictionary? You have all those lexicographers, poor dears, mumbling to themselves over their mountains of citations, hour after hour, in a way that, if you were assigned to do it, would make you want to scream and break things. Get the benefit of their labor. The Oxford English Dictionary and Merriam-Webster's Unabridged, if you have access, offer a wealth of historical information. American Heritage has extensive usage advice. You're supposed to be writing in ways that people understand, so pay attention to what people think words mean.
Item: What do the manuals say? Chicago and the AP Stylebook offer advice, which you should take cautiously. Garner's Modern American Usage is the most reliable prescriptive manual, and Merriam-Webster's Dictionary of English Usage will describe the range of usage, so that you can form an opinion.
Item: What do authorities say? By authorities, I mean the people I keep pointing you toward: the lexicographers at Lanuage Log, Bill Walsh, Jan Freeman, Jonathon Owen, Tom Freeman the Stroppy Editor, and the others whose names you have come to recognize as you read these posts. I recommend informed writers to you, not the clamoring peeververein.
Item: What register are your working in? It's unlikely that advice on usage will be universally applicable on all occasions. Are you editing a formal or technical text? A conversational one? A colloquial one? A slangy one? What usage best fits the tone of your publication and the expectations of your readers? Give up on one-size-fits-all.
Just do it. It's your language too, and your tastes and judgments count, particularly if you have been set up to be an editor. Though your grammar has been fudge, if through authorities you trudge, you can be a judge, and a good judge too.