Poisoning enemies and launching invasions can take a toll on one’s health, so chances are Vladimir Putin’s doctors will be advising him to take some time off work if there’s any truth to the reports that he is set to undergo an operation. The problem with confirming the reports is that Mr. Putin’s physicians are a lot more tight-lipped than Britain’s tabloid press, which has been rife in recent days with speculation about the Russian strongman’s health.

Were Mr. Putin to undergo surgery for something as serious as cancer, it could affect the war in Ukraine because if incapacitated for even a few hours the reviled dictator would have to temporarily hand over the keys to the Kremlin. The likeliest leadership candidate in such an eventuality is said to be the hardline Russian Security Council head, Nikolai Patrushev,  the ex-FSB chief who at 70 is one year older than Mr. Putin. Under the Russian constitution, power should pass to the current prime minister, Mikhail Mishustin, but reports seem to indicate that would not happen.

Whether a serious operation is really on the table for Mr. Putin is open to question. The assertion first appeared on the semi-anonymous Telegram channel General SVR, which is reportedly run by a former Russian foreign intelligence official who goes by a pseudonym, Viktor Mikhailovich. In a hint that Mr. Mikhailovich’s claim may be politically motivated, the post called Mr. Patrushev “an outright villain … moreover, he is a more cunning, and I would say, more insidious person than Vladimir Putin.” The post issued a veiled threat to stop any such transfer of power. 

The Kremlin has been characteristically tight-lipped about the state of the Russian leader’s health, but recent photos of Mr. Putin clutching one end of a table while sitting somewhat slouched during a recent televised meeting with his defense minister, Sergei Shoigu, fueled rumors of illness. Exiled Russian journalists have previously suggested that Mr. Putin might have thyroid cancer; there have also been suggestions of abdominal cancer. The Daily Mail reported that “attention has focused recently on his behavior to control a seeming involuntary shake in his hand — renewing speculation of Parkinson’s first highlighted in 2020 by General SVR.”

It is the almost breathtaking lack of confirmed information that keeps the rumor mill about the Russian dictator’s health running at full tilt. The absence of verifiable details invites conjecture and analysis of Mr. Putin’s every move, wobbly or not. Rumors claiming he has thyroid cancer, serious back problems, or even psychosis have become part of the regular discourse surrounding the enigmatic Russian president, the German website Deutsche Welle says.

If Washington is aware of any major Putin health problems, it has not yet given an indication. The New York Post reported that when asked about the report Monday, the Pentagon spokesman, John Kirby, said, “I have seen nothing that could help us corroborate that.”