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.
No evidence has emerged to substantiate the claim, or many earlier ones, and the leaked document gives no indication that the United States finds it credible. In July, the director of the C.I.A. dismissed speculation about Mr. Putin’s health, and many Russia experts find no reason to doubt him.
Analysts called the public discussion of Mr. Putin’s well-being unsurprising. It is a predictable byproduct of the aura of mystery around powerful autocrats who keep their distance from observers and their personal lives well concealed, said John Sipher, a former C.I.A. official who ran the agency’s Russia operations.
In recent years, North Korea’s leader, Kim Jong-un, has been the subject of seemingly unfounded claims that he was gravely ill or even dead. Similar speculation has focused on President Xi Jinping of China, particularly when he stopped traveling abroad during the coronavirus pandemic.
“I’ve never put much stock in health talk,” Mr. Sipher said. “We’ve heard the same stuff for years. I just think that it’s always a discussion point in closed societies where they hide and lie about everything.”
The claim about Mr. Putin is one of many to emerge since he launched a full-scale invasion of Ukraine in February last year. Some analysts suggested that his critics spread disinformation to undermine his image as a vigorous and menacing tough guy.
In an interview with ABC News in early January, Ukraine’s military intelligence chief, Kyrylo Budanov, broadly endorsed the rumors. “He has been sick for a long time. I am sure he has cancer,” Mr. Budanov said. “I think he will die very quickly. I hope very soon.”
Two weeks later, Ukraine’s president, Volodymyr Zelensky, went even further, questioning whether Mr. Putin was still alive.
The latest example of speculation is in one of the documents that Airman First Class Jack Teixeira, whom federal agents arrested this month, is accused of leaking. It asserts that a member of Ukraine’s parliament, Yelizaveta Bohutska, claimed to know about a plan by Russian officials to undermine their own military to “sabotage” Mr. Putin.
Ms. Bohutska said the plan was to engineer a military setback by March 5, “when Putin was allegedly scheduled to start a round of chemotherapy and would thus be unable to influence the war effort,” the document states.
Ms. Bohutska disclosed the plot on Feb. 17 to Andriy Yermak, the chief of staff to Mr. Zelensky, according to the document. Ms. Bohutska, it added, had “received the information from an unidentified Russian source with access to Kremlin officials.” Neither Ukrainian official responded to requests for comment.
The document did not indicate how the United States knew about the conversation, but the leaked reports confirm suspicions that the Biden administration has been surveilling Ukraine’s government and other allies.
Subsequent events have not borne out the claims. While Mr. Putin made no public appearances on March 5, according to a Kremlin archive of his activities, that date fell on a Sunday, when he would usually not be active in public. And Mr. Putin had numerous meetings the following week.
Nor is there evidence that Russian forces experienced a surprising setback around that time.
Social media sleuths have long seized upon videos of Mr. Putin’s public appearances, claiming to identify changes in his appearance, speech, gait, or posture as evidence of faltering health.
“Fiction and falsehood,” the Kremlin spokesman, Dmitry Peskov, said last April when asked about the cancer rumors, according to a post on Telegram by the veteran Russian journalist Alexei Venediktov.
That appears to be a rare point of agreement between Russian and American officials. Asked about Mr. Putin’s health at the annual Aspen Security Forum in July, C.I.A. Director William J. Burns did not hesitate. “There are lots of rumors about President Putin’s health,” Mr. Burns said. “And as far as we can tell, he’s entirely too healthy.”
Mr. Sipher and others pointed to a recent development that does not offer encouragement to those hoping Mr. Putin’s days may be numbered: an account from a recent defector from Mr. Putin’s elite security service, Gleb Karakulov.
A secure communications specialist who fled Russia in October, Mr. Karakulov has called Mr. Putin a war criminal and would seemingly be happy to substantiate bad news about his condition.
But in an interview with The Associated Press this month, Mr. Karakulov did the opposite. If anything, he said, Mr. Putin is in better health than most people his age.
