Is Putin’s inner circle wobbling?

Vladimir Putin isn’t new to leadership crises. The first came 24 years ago this month, when Russia’s Kursk submarine sank in the Barents Sea, killing 118 crew members. Mr. Putin was vacationing on the Black Sea and slow to respond—a public-relations disaster.

Yet the latest crisis—Ukraine’s unanticipated invasion of Russia’s Kursk district and the forced evacuation of thousands of civilians—may test his grip on power as never before. Pro-Kremlin military bloggers have begun to question Moscow’s defense establishment, and at least one oligarch has publicly denounced the war.

Mr. Putin has had to deal with discontent since the conflict began. His security team, including then-security council secretary Nikolai Patrushev, was noticeably uneasy when the president previewed his Ukrainian invasion at a televised meeting in February 2022. The posse got in line, but discontent emerged again when Mr. Putin failed initially to rein in Wagner Group mercenary chief Yevgeny Prigozhin in June 2023.

Mr. Patrushev gave a speech in November discussing Mr. Putin only in the past tense, which spawned rumors of the Russian leader’s death. Around the same time he lamented the exodus of scholars and scientists from Russia because of the war. Mr. Patrushev got his due in May, when Mr. Putin removed him from his security council leadership post and gave him the ignominious job of advising the president on shipbuilding.

Yet the choir of discontent gained a new member this month when Oleg Deripaska—one of Russia’s richest businessmen—spoke up. In an Aug. 5 interview with Nikkei Asia, he criticized the Kremlin’s defense spending, called the Ukraine war “mad,” and urged an “immediate, unconditional cease-fire.”

This isn’t the first time Mr. Deripaska has criticized the war. Shortly after the invasion, he wrote on Telegram that “we need peace as fast as possible.” According to Nikkei Asia, however, he hasn’t been as “publicly critical since Russian authorities seized a hotel complex he owned in Sochi in December 2022.”

His recent comments, coming as the Kremlin was caught off guard by Ukraine’s invasion, thus caused a stir on Russian social media. Alexander Dugin, a Russian political philosopher and activist, wrote on Telegram on Aug. 9: “Previously, Deripaska’s position on the SVO”—a Russian acronym for “special military operation,” as Moscow refers to the Ukraine war—“was ambiguous. Now he has made up his mind. He is on the other side. This is a stab in the back of our people and assistance to the Ukrainian Armed Forces terrorists who invaded the Kursk region. What an oligarchy we have here.”

Mr. Deripaska rose to prominence in the ’90s, founding the investment group Basic Element in 1997 and Rusal, an aluminum company, in 2000. He married—and later divorced—the daughter of Valentin Yumashev, Boris Yeltsin’s son-in-law and former chief of staff. Mr. Deripaska earned Mr. Putin’s favor when Basic Element did much of the construction for the 2014 Winter Olympics in Sochi. Robert Mueller later investigated him as part of the probe into Russia’s potential involvement in America’s 2016 election, owing to his connections with Donald Trump’s former campaign manager Paul Manafort. The U.S. Treasury in 2018 imposed sanctions against him—along with Basic Element and several of his other companies—“in response to Russia’s worldwide malignant activity.”

Mr. Putin likely won’t dispose of Mr. Deripaska as he might other figures, say, in a plane crash or a push out of a window. As Mr. Deripaska told Nikkei Asia, “[The Kremlin] don’t touch me, and we [businessmen] stay out of politics.” He likely wouldn’t have spoken so candidly if other members of the business and political elite didn’t agree with him. As political analyst Abbas Gallyamov observed on Telegram, “Deripaska is a very analytical person, so before saying such things, he always absorbs the mood of other elites.” “This is not the voice of Deripaska alone.”

Mr. Patrushev, popular among Russian security and intelligence circles, may be among those elites. In a November meeting with security officials he expressed concern with Ukrainian sabotage in the Kursk, Belgorod and Bryansk regions. He noted that damage from attacks had cost more than seven billion rubles and advocated systematic measures to protect these regions. One can imagine Mr. Patrushev uttering “I told you so” under his breath when Mr. Putin discussed Ukraine’s surprise attack at a security council meeting this month.

Russia has made only modest military progress after 2½ years of conflict, which has spread across Russia’s borders. It has suffered around 500,000 casualties and is draining its coffers. Ordinary Russians, fed a steady stream of propaganda about defending their country against the “evil” West, are unlikely to protest. But Mr. Putin’s support among elites, essential to his remaining in power, is less certain. He shouldn’t assume they will always back a war with no end in sight.

Ms. Knight is author, most recently, of “The Kremlin’s Noose: Putin’s Bitter Feud With the Oligarch Who Made Him Ruler of Russia.”