What to do with possible duplicates that have already accepted answers?

Question

I belatedly realized that a fairly recent question is very similar to an older question. However, the recent question already has an accepted answer (disclaimer: mine) and the older question does not.

I'm not quite sure what to do. Aaronut's answer in a related meta thread states that:

If you see a new question that's a duplicate of an old question, voting to close usually covers it - most of the time, the question will get closed before any answers get posted - or at least any answers worth keeping. In that case, merging is fairly pointless...

That apparently didn't happen here, and I do hope that my answer is worth keeping. However, Sobachatina's highest-ranking answer to the old question has a lot of good information too. I'm further thrown off by another statement from Aaronut:

It's very, very rare for a moderator to merge questions that have only been recently closed, and almost unheard of to merge questions that are still open (I'm not even sure if it's allowed). That's because its dupe status may still be in dispute at that point, and merges can't be undone like closures can.

I find it doubtful that there's any dispute over the status of the older question at this point, but it looks like merging may not even be possible here.

Does this situation merit further action? If so, what's the best solution?

Answer 1

Closing as a duplicate is always good when the two questions are the same. We want one exhaustive source on each topic.

The situation is indeed easier when the new question doesn't gain traction, a closing suffices then. Merging is usually done when both questions have answers good enough to be preserved.

I see the pair you pointed out as a clear merging candidate. I would tend to keep the old question, in this case not because of its age, but because it is the more general one. And I also see your answer as good enough to be saved after the closing, so merging is better than pure closure. In fact, other sites on the network delete very old closed questions, so there is a chance it will disappear one day if we start following this rule too.

The second citation by Aaronut is a good one, especially the reason for no immediate merging. I think I will close it first and wait a few days. If there are no objections to the closure (or objections arise and get resolved), we can merge then.