You say "General's," I say "General"?

So, what is that thing that one alternately praises or disparages, depending on whether it agrees with one's client's position -- an attorney general opinion, or an attorney general's opinion?

Garner's Dictionary of Modern Legal Usage appears silent on the question. 81 MSSC/COA opinions use "general" and 64 use "general's"; some, charmingly, use both: "Swan sought and obtained an Attorney General opinion. The Attorney General's opinion stated ...."

Turning to the ALLSTATES database in Westlaw and confining the search to 1980 and after, I get 1835 hits for the usage with the apostrophe "s" and 2956 for the usage without, not far from the MS-CS proportion.

... And if there's no apostrophe "s," then does "attorney general" take a hyphen? I'm going with "no," but more out of revulsion than logic.

... By analogy, one says "There's a supreme court opinion on point," not "a supreme court's opinion. But "The supreme court's opinion." Hm.

Here is the solution: "An opinion issued by the Attorney General's office (hereinafter 'AG Opinion') stated that ...."