WASHINGTON — For more than a year, the notion that Vladimir V. Putin is seriously ill has been a subject of lurid speculation, internet video forensics — and potential wartime propaganda, even though U.S. officials say there is no evidence the Russian leader is dying.
Now, a document among the trove of leaked classified materials offers the latest example of the fascination with Mr. Putin’s health. It describes a conversation between two Ukrainian officials about what one claimed was a conspiracy among Mr. Putin’s internal opponents to challenge his rule at a moment when he was said to be undergoing chemotherapy.
