Suppose that a question has an answer which is correct and was upvoted, but which has been deleted (along with the account responsible). Is it acceptable to copy the content of such an answer and repost it, with as much attribution as can be given?
The obvious argument in favor is that the content seems genuinely useful to MSE and to any future readers of the question, and any users under 10k reputation would be well-served by having access to that material. The obvious concern is that perhaps the user who deleted it had some reason for doing so, and doesn't want their writing any more accessible than it already is. (But if they wanted that, wouldn't they at least have edited the deleted answer to obfuscate its contents more?)
In the particular case I'm considering, it seems like the answer is not much more than a reference to a known theorem, and so I don't feel especially squeamish about unauthorized reposting of deeply original work. Still, it doesn't seem to be something with established conventions, and I can imagine thornier cases than this one, so I wanted to solicit opinions about this behavior in general.
(If the author hasn't deleted their account, it seems like one should just ask them why the answer was deleted in a comment, but that avenue isn't available here.)