Instead of down voting me, you could reply saying that this article has new details (like the leaked presentation). I just assumed it was a repost of yesterday's discussion.
My practice is to usually limit "dupe" to the identical link or story submitted multiple times. Major mainstream breaking news possibly excepted.
For different takes on the same story, "Previously" with a link to earlier discussion, may be better.
For evergreen topics (e.g., Bertrand Russell's "In Defence of Idleness", submitted many times through the years, and again a day or so back), "earlier submissions" noting the years, of 2-3 top instances, can point to earlier interesting discussion.